Polyurethane compositions for golf balls

ABSTRACT

Polyurethane and polyurea compositions for golf balls with improved stability of the curative blend, wherein the curative blend includes a pigment, a curing agent, and a compatible freezing point depressing agent so that the curative blend has a lower freezing point than the curing agent by itself and the blend does not lose pigment dispersion upon solidification and subsequent thawing.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 10/194,057, filed Jul. 15, 2002, now U.S. Pat. No. 6,867,279,which is a continuation-in-part of U.S. patent application Ser. No.09/466,434, filed Dec. 17, 1999, now U.S. Pat. No. 6,476,176. Thisapplication is also a continuation-in-part of U.S. patent applicationSer. No. 10/228,311, filed Aug. 27, 2002, now U.S. Pat. No. 6,835,794,which is a continuation-in-part of U.S. patent application Ser. No.09/466,434, filed Dec. 17, 1999, now U.S. Pat. No. 6,476,176 and acontinuation-in-part of U.S. patent application Ser. No. 09/951,963,filed Sep. 13, 2001, now U.S. Pat. No. 6,635,716, and which claimspriority to U.S. Patent Provisional Application No. 60/401,047, filedAug. 6, 2002. This application is also a continuation-in-part of U.S.patent application Ser. No. 09/812,910, filed Mar. 20, 2001 now U.S.Pat. No. 6,506,851, which is a continuation of U.S. patent applicationSer. No. 09/466,434, filed Dec. 17, 1999, now U.S. Pat. No. 6,476,176.The entire disclosures of these applications are incorporated byreference herein.

FIELD OF THE INVENTION

The invention relates to polyurethane and polyurea compositions for golfballs with improved pigment dispersion and stability of the curativeblend. In particular, the present invention is directed to a curativeblend that includes a curing agent and a freezing point depressingagent, wherein the curative blend has a lower freezing point than thecuring agent by itself and the blend does not lose pigment dispersionupon solidification and subsequent thawing. The present invention alsorelates to polyurethane compositions formed from prepolymers ofisocyanate and polyol, of which the prepolymer is crosslinked with theimproved curative blend of the invention. In addition, polyureacompositions are contemplated by the present invention, in which thepolyurea composition is the reaction product of a polyamine and anisocyanate cured with modified curative blends based on at least oneamine-terminated curing agent. The invention also relates to golf ballcomponents formed from the composition of the invention and the methodof making the components.

BACKGROUND OF THE INVENTION

Golf balls are formed from a variety of compositions, which provides agolf ball manufacturer the ability to alter feel and aerodynamiccharacteristics of a particular ball. For example, golf ball coversformed from balata allow a highly skilled golfer to achieve spin ratessufficient to more precisely control ball direction and distance,particularly on shorter shots. Balata covered golf balls are easilydamaged, however, which discourages the average golfer from using suchballs. To remedy this durability issue, manufacturers typically useionomer resin as a cover material. However, while ionomer resin coveredgolf balls possess virtually cut-proof covers, the spin and feel areinferior compared to balata covered balls.

Polyurethanes and polyureas have also been recognized as usefulmaterials for golf ball covers since the resulting golf balls aredurable like ionomer resin, but have the soft feel of a balata coveredgolf ball. U.S. Pat. No. 4,123,061 teaches a golf ball made from apolyurethane prepolymer formed of polyether with diisocyanate that iscured with either a polyol or an amine-type curing agent. In addition,U.S. Pat. No. 5,334,673 discloses the use of two categories ofpolyurethane available on the market, i.e., thermoset and thermoplasticpolyurethanes, for forming golf ball covers and, in particular,thermoset polyurethane covered golf balls made from a composition ofpolyurethane prepolymer and a slow-reacting amine curing agent, and/or adifunctional glycol. U.S. Pat. No. 5,484,870 discloses a polyureacomposition comprising the reaction product of an organic diisocyanateand an organic amine, each having at least two functional groups. Oncethese two ingredients are combined, the polyurea is formed and, thus,the ability to vary the physical properties of the composition islimited.

While polyurethane and polyurea covered golf balls are softer thanionomer resin covered golf balls, such balls do not fully match ionomerresin golf balls with respect to resilience or the rebound of the golfball cover, which is a function of the initial velocity of a golf ballafter impact with a golf club. Furthermore, because the polyurethanesand polyureas used to make the covers of such golf balls generallycontain an aromatic component, e.g., aromatic diisocyanate, polyol, orpolyamine, they are susceptible to discoloration upon exposure to light,particularly ultraviolet (UV) light. To slow down the discoloration,light and UV stabilizers, e.g., Tinuvin 770, 765, and 328, are added tothese aromatic polymeric materials. However, to further ensure that thecovers formed from aromatic polyurethanes do not appear discolored, thecovers are painted with white paint and then covered with a clear coatto maintain the white color of the golf ball. The application of auniform white pigmented coat to the dimpled surface of the golf ball isa difficult process that adds time and costs to the manufacture of agolf ball.

In addition, the curing agents typically used in polyurethanecompostions have relatively high freezing points, which make shippingand storage of these materials during the winter season problematic.This problem is compounded when the compositions include pigments. Forexample, when certain curatives have thawed from a frozen state, thesolids separate and the quality of the pigment dispersed therein can belost, as measured by the Hegman scale. The Hegman scale is a measurementof particle size, which is-typically used to denote the degree ofpigment dispersion. When a material completely loses its quality ofdispersion (Hegman equals 0), the particle size of the material isgenerally about 100 microns or greater. For example, a curative thatcontains pigment, such as 1,4-butanediol, loses pigment dispersionquality upon freezing. To overcome this loss of pigment dispersion, theseparated blend would need to be redispersed before being incorporatedinto various compositions. In cases where the pigment has undergone“hard settling,” however, the pigment cannot be redispersed and theblend is rendered unusable.

There remains a continuing need for improved compositions that areeasily processed into golf balls having performance characteristics,improved resilience, increased cut, scratch and abrasion resistance,enhanced adherence, and improved light stability. Thus, there alsoremains a need for improved curative blends, particularly those in whichthe pigment is dispersed, that are able to withstand lower temperaturestorage and shipping conditions. In addition, it would be advantageousto provide such agents that, even if frozen, are still able to be usedwithout redispersing the pigment or without sacrificing properties ofthe resin. In particular, the addition of a freezing point depressingagent to a curative blend that results in a storage stable pigmentdispersion would be advantageous to use in golf ball compositions.

SUMMARY OF THE INVENTION

The present invention is directed to improved curative blends for use inpolyurethane and polyurea compositions that result in golf balls withimproved durability, adherence, and light stability. One aspect of thepresent invention relates to a golf ball including a core and a cover,wherein the cover is formed from a composition including: a polyurethaneprepolymer formed from the reaction product of an isocyanate and apolyol; and a curative blend formed from at least one curing agent andat least one compatible freezing point depressing agent.

In one embodiment, the at least one curing agent has a first freezingpoint and the curative blend has a second freezing point less than thefirst freezing point by about 5° F. or greater, preferably about 10° F.or greater, and more preferably about 15° F. or greater. In anotherembodiment, the freezing point depressing agent has a freezing point ofabout 10° F. or less, preferably about −10° F. to about −100° F.

The freezing point depressing agent may include hydroxy-terminatedfreezing point depressing agents selected from the group consisting of1,3-propanediol, 2-methyl-1,3-propanediol, 2-methyl-1,4-butanediol,1,2-butanediol, 1,3-butanediol, ethylene glycol, diethylene glycol,1,5-pentanediol, polytetramethylene glycol, propylene glycol, andmixtures thereof. In one embodiment, the freezing point depressing agentis present in an amount of about 8 percent or greater by weight of thecurative blend, preferably about 10 percent or greater by weight of thecurative blend.

The curative blend preferably has a pigment dispersion of about 4 orgreater on the Hegman scale. In one embodiment, the curative blend has apigment dispersion of about 5 or greater on the Hegman scale.

The polyurethane prepolymer may be unsaturated or saturated, but whenthe prepolymer is saturated, the curative blend is also preferablysaturated.

The present invention is also directed to a golf ball including a coreand a light stable cover, wherein the cover is formed from a compositionincluding: a polyurethane prepolymer formed from the reaction product ofan isocyanate and a polyol; and a pigment dispersed in a curative blendincluding at least one curing agent and at least freezing pointdepressing agent. In one embodiment, the curative blend has a pigmentdispersion of about 4 or greater after a freeze/thaw cycle. In anotherembodiment, the pigment is contained in a grind vehicle. The at leastone curing agent has a first freezing point and the curative blend has asecond freezing point, and wherein the second freezing point ispreferably less than the first freezing point by about 10° F. orgreater. In one embodiment, the freezing point depressing agent ispresent in an amount of about 10 percent or greater by weight of thecurative blend.

The cover layer may be formed from casting, injection molding, orreaction injection molding and may have a thickness of about 0.02 inchesto about 0.035 inches. In addition, the polyol included in thepolyurethane prepolymer is preferably selected from the group consistingof saturated polyether polyols, saturated polycaprolactone polyols,saturated polyester polyols, saturated polycarbonate polyols, saturatedhydrocarbon polyols, aliphatic polyols, and mixtures thereof. The atleast one curing agent is preferably selected from the group consistingof ethylene glycol; diethylene glycol; polyethylene glycol; propyleneglycol; 2-methyl-1,3-propanediol; 2,-methyl-1,4-butanediol; dipropyleneglycol; polypropylene glycol; 1,2-butanediol; 1,3-butanediol;1,4-butanediol; 2,3-butanediol; 2,3-dimethyl-2,3-butanediol;trimethylolpropane; cyclohexyldimethylol; triisopropanolamine;tetra-(2-hydroxypropyl)-ethylene diamine; diethylene glycoldi-(aminopropyl)ether; 1,5-pentanediol; 1,6-hexanediol;1,3-bis-(2-hydroxyethoxy)cyclohexane; 1,4-cyclohexyldimethylol;1,3-bis-[2-(2-hydroxyethoxy)ethoxy]cyclohexane;1,3-bis-{2-[2-(2-hydroxyethoxy)ethoxy]ethoxy}cyclohexane;trimethylolpropane; polytetramethylene ether glycol; and mixturesthereof.

In one embodiment, the composition further includes at least onecatalyst, at least one light stabilizer, at least one defoaming agent,at least one acid functionalized moiety, at least one fragrancecomponent, or combinations thereof.

The present invention is also directed to a golf ball including a coverand a core, wherein at least one of the cover or the core includes asolvent-free pigment dispersion, wherein the pigment dispersion can befrozen, thawed, and used without redispersing the pigment. This pigmentdispersion, which may also be referred to as a curative blend for thepurposes of this invention, preferably includes at least one pigment anda blend of at least two active hydrogen-containing materials. In oneembodiment, the at least two active hydrogen-containing materials havedifferent freezing points. For example, the at least two activehydrogen-containing materials may comprise a first activehydrogen-containing material that has a higher freezing point than thefreezing point of the second active hydrogen-containing material. Inthis aspect of the invention, the first active hydrogen-containingmaterial may be a curing agent and the second active hydrogen-containingmaterial may include 1,3-propanediol, 2-methyl-1,3-propanediol,2-methyl-1,4-butanediol, 1,2-butanediol, 1,3-butanediol, ethyleneglycol, diethylene glycol, 1,5-pentanediol, polytetramethylene glycol,propylene glycol, or mixtures thereof. The pigment dispersion of thecurative blend preferably measures about 4.0 or greater on the Hegmanscale.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the invention can be ascertained fromthe following detailed description that is provided in connection withthe drawing(s) described below:

FIG. 1 is a cross-sectional view of a two-piece golf ball, wherein thecover is formed from the polyurethane or polyurea compositions of theinvention;

FIG. 2 is a cross-sectional view of a multi-component golf ball, whereinat least the cover is formed from the polyurethane or polyureacompositions of the invention;

FIG. 3 is a cross-sectional view of a multi-component golf ball, whereinthe cover is formed from the polyurethane or polyurea compositions ofthe invention and the intermediate layer is formed from a compositionincluding at least one ionomer resin;

FIG. 4 is a cross-sectional view of a multi-component golf ballincluding a core and a cover, wherein the core is surrounded by atensioned elastomeric material and the cover is formed from thepolyurethane or polyurea compositions of the invention;

FIG. 5 is a cross-sectional view of a liquid center golf ball whereinthe liquid core is surrounded by a tensioned elastomeric material andthe cover is formed from the polyurethane or polyurea compositions ofthe invention;

FIG. 6 is a cross-sectional view of a multi-component golf ballincluding a core, a thin inner cover layer, and a thin outer cover layerdisposed thereon, wherein the cover is formed from the polyurethane orpolyurea compositions of the invention;

FIG. 7 is a cross-sectional view of a multi-component golf ballincluding a core, an outer core layer, a thin inner cover layer, and athin outer cover layer disposed thereon, wherein the cover is formedfrom the polyurethane or polyurea compositions of the invention; and

FIG. 8 is a cross-sectional view of a multi-component golf ballincluding a large core and a thin outer cover layer disposed thereon,wherein the cover is formed from the polyurethane or polyureacompositions of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention contemplates improved polyurethane- andpolyurea-based compositions for use in various golf ball components. Thecompositions of the invention may be included in a variety of golf ballconstructions, i.e., one-piece, two-piece, or multilayer balls. Inaddition, the compositions of the invention are also intended for use ingolf club components, e.g., club head inserts.

In particular, the curative blend used in the compositions of theinvention are modified with a freezing point depressing agent so thatthe freezing point of the blend is less than the freezing point of thecuring agent by itself and so that any pigment dispersed within theblend stays dispersed under a host of storage and shipping conditions.Thus, this modified curative blend results in a storage stable pigmentdispersion. As used herein, the term “storage stable” refers to theability of a dispersion, blend, composition, or the like, to resistfreezing at room temperature (about 68° F. to about 77° F.) and below(down to about −15° F.), as well as the ability of the dispersion,blend, composition, or the like to retain their beneficial properties,such as adhesive strength, shear/cut resistance, hardness, anddurability, even if frozen. For example, the modifed curative blends ofthe present invention maintain pigment dispersion quality when frozenand also after a freeze/thaw cycle.

The inclusion of the modified curative blends in polyurethane orpolyurea compositions, which are incorporated into various golfcomponents, e.g., covers, result in golf balls with physical andaerodynamic properties better than or equal to golf balls incorporatingpolyurethane or polyurea compositions without modified curative blends.

The compositions of the invention may be thermoset or thermoplastic innature and are preferably saturated, i.e., substantially free ofunsaturated carbon—carbon bonds or aromatic groups, to produce a lightstable composition. Light stability may be accomplished in a variety ofways for the purposes of this application. For example, the compositionsof the invention may include only saturated components, i.e., saturatedprepolymers and saturated curing agents, or include a light stabilizerto improve light stability when using aromatic components.

Modified Curative Blend

The curing agent of the invention may be modified with a freezing pointdepressing agent to create a curative blend with a slower onset ofsolidification and with storage stable pigment dispersion. In otherwords, the curing agent is preferably modified with a freezing pointdepressing agent to produce a curative blend that has a lower freezingpoint than the unmodified curing agent. As such, the modified curativeblend results in an improved medium for pigment, such that pigment(s)contained in the modified curative blend remain in dispersed forminstead of forming agglomerates when frozen.

Pigment dispersion is generally evaulated by the Hegman scale, which isa measure of particle size. The Hegman scale measures the fineness ofthe ground pigment, i.e., the degree of dispersion and consistency ofparticle size, and ranges from zero (particle sizes of greater thanabout 100 microns) to 8 (sub-micron particle sizes). A poor qualitypigment dispersion (greater than about 100 microns), for example, woulddenote large pigment particles or large agglomerates, which may limitthe application of the dispersion. The pigment dispersion measurement istaken by drawing down a sample of a grind block, wherein the face of thegrind block is surfaced so that particles of a particular size willvisibly protude on the block at designated intervals.

After freezing and subsequent thawing, the modified curative blend ofthe present invention preferably has a pigment dispersion of greaterthan 0 on the Hegman scale, preferably about 1 or greater, and morepreferably about 2 or greater. In one embodiment, the modified curativeblend after a freeze/thaw cycle has a pigment dispersion of about 3 orgreater on the Hegman scale. In another embodiment, the modifiedcurative blend after a freeze and thaw is about 4 or greater on theHegman scale, preferably about 5 or greater. In still anotherembodiment, the modified curative blend after a freeze and thaw is about6 or greater on the Hegman scale. In yet another embodiment, themodified curative blend after freezing and thawing is about 7 or greateron the Hegman scale.

The modified curative blend, after a freeze/thaw cycle, preferably has aparticle size of about 100 microns or less, more preferably about 89microns or less, and even more preferably about 76 or less. In oneembodiment, the particle size of the modified curative blend is about 64or less. In another embodiment, the particle size of the modifiedcurative blend is about 51 or less. In still another embodiment, themodified curative blend has a particle size of about 38 or less,preferably about 25.4 or less. In yet another embodiment, the particlesize of the modified curative blend is about 19.1 or less, preferablyabout 12.7 or less.

The mesh size of the modified curative blend is also an indicator ofpigment dispersion, i.e., the smaller the mesh size, the better thepigment dispersion. Thus, in one embodiment, the mesh size of themodified curative blend after a freeze/thaw cycle is about 140 orgreater, preferably about 170 or greater, and more preferably about 200or greater. In one embodiment, the mesh size of the modified curativeblend is from about 140 to about 1000. In another embodiment, the meshsize is about 230 or greater. In yet another embodiment, the mesh sizeis about 270 or greater, preferably about 400 or greater, and morepreferably about 500 or greater.

Because the modified curative blend of the present invention results ina storage stable pigment dispersion, any compatible pigment may bedispersed in the modified curative blend of the invention, even thosethat generally are problematic with respect to maintaining dispersion.For example, titanium dioxide is known to be difficult to maintain indispersion because of the high concentrations typically used to obtainopacity, but the present invention provides a solution to this problem.Thus, non-limiting examples of suitable pigments include titaniumdioxide (TiO₂), inorganic pigments such as red or yellow iron oxides,carbon black, and ultramarine blue, organic pigments such asphthalocyanine blue, phthalocyanine green, carbazole violets, andnaphthol reds, and mixtures thereof.

In addition, the pigment may be incorporated into a premade colorant ortint, such as those commercially available from Polyone Corporation ofAvon Lake, Ohio. These premade colorants or tints generally contain apigment(s) dispersed in a grind vehicle, e.g., high molecular weightpolyols. While these grind vehicles may introduce small, quantities ofactive hydrogen containing materials to the curative blends of theinvention, these quantities are not a significant contribution to themodified curative blend of the invention.

The pigment is preferably dispersed in a blend of activehydrogen-containing materials, e.g., the modified curative blend mayinclude at least one pigment, at least one curing agent (first activehydrogen-containing material), and at least one freezing pointdepressing agent (second active hydrogen-containing material). An activehydrogen-containing material, as used herein, is a material thatcontains at least one hydrogen that is reactive, which may occur byhaving a hydroxyl, primary amino, secondary amino, or thiol group. Theactive hydrogen-containing materials are generally describable asmonomers or oligomers, rather than polymers or resins. “Monomer” will beunderstood as referring to molecules or compounds having a relativelylow molecular weight and a simple structure capable of conversion to apolymer, resin or elastomer by combination with itself or other similarmolecules or compounds. An oligomer is a combination of only a few (i.e.4 or less) monomers. A polymer, in contrast, comprises 5 or more of suchunits. For example, in one embodiment, the active hydrogen-containingmaterials included in the modified curative blend of the presentinvention have a number average molecular weight of between about 30 andabout 4000. In another embodiment, the number average molecular weightof the active hydrogen-containing materials is from about 90 to about1000.

Any combination of active hydrogen-containing materials is contemplatedby the present invention and the selection of materials is not limitedto those expressly listed herein, as long as the blend is liquid at roomtemperature and below. Those of ordinary skill in the art will be ableto determine the freezing point of a blend, using the standard freezingpoint determination. For example, an empirical method of freezing pointdetermination is to cool the sample, which may be done by surrounding itwith an ice bath while stirring, and record the temperature at regularintervals, e.g., every minute, until the material begins to solidify. Assolidification occurs, the temperature begins to level off, whichsignifies the freezing point of the material. In addition, analyticalmethods of determining the freezing point may also be used such asDifferential Scanning Calorimetry (DSC).

The active hydrogen-containing materials may include curing agents, suchas hydroxy-terminated curing agents or amine-terminated curing agents.Suitable hydroxy-terminated curing agents include, but are not limitedto, ethylene glycol; diethylene glycol; polyethylene glycol; propyleneglycol; 2-methyl-1,3-propanediol; 2,-methyl-1,4-butanediol; dipropyleneglycol; polypropylene glycol; 1,2-butanediol; 1,3-butanediol;1,4-butanediol; 2,3-butanediol; 2,3-dimethyl-2,3-butanediol;trimethylolpropane; cyclohexyldimethylol; triisopropanolamine;tetra-(2-hydroxypropyl)-ethylene diamine; diethylene glycoldi-(aminopropyl)ether; 1,5-pentanediol; 1,6-hexanediol;1,3-bis-(2-hydroxyethoxy)cyclohexane; 1,4-cyclohexyldimethylol;1,3-bis-[2-(2-hydroxyethoxy)ethoxy]cyclohexane;1,3-bis-{2-[2-(2-hydroxyethoxy)ethoxy]ethoxy}cyclohexane;trimethylolpropane; polytetramethylene ether glycol, preferably having amolecular weight ranging from about 250 to about 3900;resorcinol-di-(beat-hydroxyethyl)ether and its derivatives;hydroquinone-di-(beta-hydroxyethyl)ether and its derivatives;1,3-bis-(2-hydroxyethoxy)benzene;1,3-bis-[2-(2-hydroxyethoxy)ethoxy]benzene;N,N-bis(β-hydroxypropyl)aniline; 2-propanol-1,1′-phenylaminobis; andmixtures thereof. The hydroxy-terminated curing agent may have amolecular weight of at least about 50. In one embodiment, the molecularweight of the hydroxy-terminated curing agent is about 2000 or less.

In addition, suitable amine-terminated curing agents include, but arenot limited to, ethylene diamine; hexamethylene diamine;1-methyl-2,6-cyclohexyl diamine; tetrahydroxypropylene ethylene diamine;2,2,4- and 2,4,4-trimethyl-1,6-hexanediamine;4,4′-bis-(sec-butylamino)-dicyclohexylmethane;1,4-bis-(sec-butylamino)-cyclohexane;1,2-bis-(sec-butylamino)-cyclohexane; derivatives of4,4′-bis-(sec-butylamino)-dicyclohexylmethane; 4,4′-dicyclohexylmethanediamine; 1,4-cyclohexane-bis-(methylamine);1,3-cyclohexane-bis-(methylamine); diethylene glycoldi-(aminopropyl)ether; 2-methylpentamethylene-diamine;diaminocyclohexane; diethylene triamine; triethylene tetramine;tetraethylene pentamine; propylene diamine; 1,3-diaminopropane;dimethylamino propylamine; diethylamino propylamine; dipropylenetriamine; imido-bis-propylamine; monoethanolamine, diethanolamine;triethanolamine; monoisopropanolamine, diisopropanolamine;isophoronediamine; 4,4′-methylenebis-(2-chloroaniline);3,5;dimethylthio-2,4-toluenediamine;3,5-dimethylthio-2,6-toluenediamine; 3,5-diethylthio-2,4-toluenediamine;3,5;diethylthio-2,6-toluenediamine;4,4′-bis-(sec-butylamino)-diphenylmethane and derivatives thereof;1,4-bis-(sec-butylamino)-benzene; 1,2-bis-(sec-butylamino)-benzene;N,N′-dialkylamino-diphenylmethane; N,N,N′,N′-tetrakis(2-hydroxypropyl)ethylene diamine;trimethyleneglycol-di-p-aminobenzoate;polytetramethyleneoxide-di-p-aminobenzoate;4,4′-methylenebis-(3-chloro-2,6-diethyleneaniline);4,4′-methylenebis-(2,6-diethylaniline); meta-phenylenediamine;paraphenylenediamine; and mixtures thereof. In one embodiment, theamine-terminated curing agent is4,4′-bis-(sec-butylamino)-dicyclohexylmethane.

As discussed above, each active hydrogen-containing material may have adifferent freezing point, e.g., a curing agent with a freezing point ofroom temperature and a second active hydrogen-containing material, e.g.,a freezing point depressing agent, with a freezing point well below roomtemperature. The selection of two active hydrogen-containing agents withdifferent freezing points results in an overall blend with a lowerfreezing point than if the curing agent were used alone. For example, inone embodiment, the differential between the freezing point of thecuring agent and the freezing point of the curative blend is about 5° F.or greater, preferably about 10° F. or greater. In another embodiment,the differential is about 15° F. or greater, preferably about 20° F. orgreater. Thus, the selection of the freezing point depressing agent iscorrelative with the selection of the other active hydrogen-containingmaterial, i.e., the curing agent.

The freezing point depressing agent preferably has a freezing point ofabout 20° F. or less, more preferably about 10° F. or less. In oneembodiment, the freezing point depressing agent has a freezing point ofabout 0° F. or less. In another embodiment, the freezing point of thefreezing point depressing agent is about −10° F. to about −120° F. Instill another embodiment, the freezing point of the freezing pointdepressing agent is about 10° F. to about 100° F. In yet anotherembodiment, the freezing point is about −30° F. to about −70° F.

Suitable freezing point depressing agents may include any agents thatstabilize the pigment dispersion of the curative blend when thetemperature drops below room temperature. For example,2-methyl-1,3-propanediol has a freezing point of −65° F. When about 10percent by weight of the 2-methyl-1,3-propanediol is added to a curativeblend containing 1,4-butane diol, which has a freezing point of 68° F.,the freezing point of the curative blend lowers to about 44° F. Thus, inone embodiment, the freezing point depressing agent is selected so thatthe freezing point of the blend is about 60° F. or less. In anotherembodiment, the freezing point depressing agent is chosen so that theblend has a freezing point of about 50° F. or less. In still anotherembodiment, the freezing point depressing agent modifies the blend sothat the freezing point of the blend is about 45° F. or less. In yetanother embodiment, the freezing point of the blend is about 32° F. orless after addition of the freezing point depressing agent.

The freezing point depressing agent is preferably compatible with thecuring agent. For example, a hydroxy-terminated curing agent such as1,4-butanediol may be modified with a hydroxy-terminated freezing pointdepressing agent or a mixture of hydroxy-terminated freezing pointdepression agents. Examples of hydroxy-terminated freezing pointdepressing agents include, but are not limited to, 1,3-propanediol,2-methyl-1,3-propanediol, 2-methyl-1,4-butanediol, 1,2-butanediol,1,3-butanediol, ethylene glycol, diethylene glycol, 1,5-pentanediol,polytetramethylene glycol, propylene glycol, dipropylene glycol, andmixtures thereof.

In addition, a number of amine-terminated curing agents have relativelyhigh freezing points, e.g., hexamethylene diamine (105.8° F.),diethanolamine (82.4° F.), triethanol amine (69.8° F.),diisopropanolamine (73.4° F.), and triisopropanolamine (111.2° F.). Suchamine-terminated curing agents may be modified with an amine-terminatedfreezing point depressing agent or a mixture of amine-terminatedfreezing point depressing agents. Suitable amine-terminated freezingpoint depressing agents include, but are not limited to, ethylenediamine, 1,3-diaminopropane, dimethylamino propylamine, tetraethylenepentamine, 1,2-propylenediamine, diethylaminopropylamine,2,2,4-trimethyl-1,6-hexanediamine, 2,4,4-trimethyl-1,6-hexanediamine,and mixtures thereof.

In one embodiment, the modified curative blend includes an alcoholhaving a molecular weight of less than about 200 and another activehydrogen-containing material that is not a dihydroxy compound, butcontains an ester group, and has a molecular weight from about 204 toabout 500.

The freezing point depressing agent is preferably added in an amountsufficient to reduce the freezing point of the curing agent by asuitable amount to prevent loss of pigment dispersion, but not affectthe physical properties of the golf ball. In one embodiment, thefreezing point depressing agent is added to the curing agent in anamount of about 5 percent or greater by weight of the curative blend,i.e., curing agent(s), freezing point depressing agent. In anotherembodiment, the freezing point depressing agent is present in an amountof about 8 percent greater by weight of the curative blend. In stillanother embodiment, the freezing point depressing agent is present in anamount of about 10 percent or greater. In yet another embodiment, thecurative blend includes the freezing point depressing agent in an amountof about 12 percent or greater by weight of the curative blend. Thecurative blend may also include a freezing point depressing agent in anamount of about 14 percent or greater by weight of the curative blend.

For example, in one embodiment of the present invention, the modifiedcurative blend includes about 90 percent by weight of a curing agent andabout 10 percent by weight of a freezing point depressing agent. Thoseof ordinary skill in the art are aware that a relatively minor portionof the modified curative blend will need to have a freezing point ofroom temperature and below in order to achieve the liquid, storagestable characteristics of the modified curative blend contemplated bythe present invention. This proper balance results in a modifiedcurative blend that retains its beneficial properties withoutsacrificing pigment dispersion or freezing at relatively hightemperatures.

The pigment is preferably included in the modified curative blend in anamount of about 10 percent to about 70 percent by weight of the totalcurative blend, i.e., curing agent(s), freezing point depressingagent(s), and pigment. In one embodiment, the pigment is included in themodified curative blend in an amount of about 15 percent to about 55percent by weight of the total curative blend. In another embodiment,the pigment is present in the modified curative blend in an amount ofabout 23 percent by weight of the total curative blend. The blend ofcuring agent(s) and freezing point depressing agent(s) is preferablyincluded in the total curative blend in an amount of about 30 percent toabout 90 percent by weight. In one embodiment, the blend of curingagent(s) and freezing point depressing agent(s) is included in the totalcurative blend in an amount of about 50 weight percent to about 80weight percent, preferably about 50 weight percent to about 70 weightpercent.

In one embodiment, the modified curative blend is substantially free ofdimethyl sulfoxide. As used herein, “substantially free” means less thanabout 3 percent by weight of the blend, preferably less than about 1percent by weight of the blend, more preferably less than about 0.5percent by weight of the blend.

The modified curative blends of the present invention may be solventfree. As used herein, “solvent free” means about 1 percent or less,preferably about 0.5 percent or less, of solvent, e.g., water, alcohol,ketones, aromatic solvents, and the like.

The modified curative blend of the present invention may be be made inany suitable manner. For example, in one method, a pigment isincorporated into a mixture of at least one curing agent and at leastone freezing point depressing agent. This may be accomplished throughblending with a cowles grind or mill grind. Alternatively, the pigmentmay added to the curing agent first, and then the curing agent/pigmentblend is combined with the freezing point depressing agent or thepigment may be added to the freezing point depressing agent beforeincorporating the curing agent. As discussed above, the pigment may betitanium dioxide (TiO₂), inorganic or organic pigments, or commerciallyavailable pigments in grind vehicles. When using a commerciallyavailable pigment in a grind vehicle, simple mixing may be employedbecause the pigment would not need to be ground into the curing agent,freezing point depressing agent, or curative blend. Standard additives,if used, may be added at any step in the process.

Polyurethane Composition

As mentioned, the compostions of the invention are polyurethane-based,i.e., a product of a reaction between at least one polyurethaneprepolymer and a curing agent, of which the polyurethane prepolymer is aproduct formed by a reaction between at least one polyol and at leastone diisocyanate. The polyurethane-based compositions of the inventionare preferably saturated and, thus, in one embodiment, the compositionof the invention is the product of a reaction between at least onesaturated polyurethane prepolymer, formed of at least one saturateddiisocyanate and at least one saturated polyol, and at least onesaturated curing agent.

Isocyanate Component

Saturated isocyanates for use with the polyurethane prepolymer includealiphatic, cycloaliphatic, araliphatic, derivatives thereof, andcombinations of these compounds having two or more isocyanate (NCO)groups per molecule. The isocyanates may be organic, modified organic,organic polyisocyanate-terminated prepolymers, and mixtures thereof. Theisocyanate-containing reactable component may also include anyisocyanate-functional monomer, dimer, trimer, or multimeric adductthereof, prepolymer, quasi-prepolymer, or mixtures thereof.Isocyanate-functional compounds may include monoisocyanates orpolyisocyanates that include any isocyanate functionality of two ormore. Suitable isocyanate-containing components include diisocyanateshaving the generic structure: O═C═N—R—N═C═O, where R is preferably acyclic or linear or branched hydrocarbon moiety containing from about 1to 20 carbon atoms. The diisocyanate may also contain one or more cyclicgroups. When multiple cyclic groups are present, linear and/or branchedhydrocarbons containing from about 1 to 10 carbon atoms can be presentas spacers between the cyclic groups. In some cases, the cyclic group(s)may be substituted at the 2-, 3-, and/or 4-positions, respectively.Substituted groups may include, but are not limited to, halogens,primary, secondary, or tertiary hydrocarbon groups, or a mixturethereof.

Examples of saturated diisocyanates that can be used in the polyurethaneprepolymer include, but are not limited to, ethylene diisocyanate;propylene-1,2-diisocyanate; tetramethylene diisocyanate;tetramethylene-1,4-diisocyanate; 1,6-hexamethylene-diisocyanate (HDI);octamethylene diisocyanate; decamethylene diisocyanate;2,2,4-trimethylhexamethylene diisocyanate; 2,4,4-trimethylhexamethylenediisocyanate; dodecane-1,12-diisocyanate; cyclobutane-1,3-diisocyanate;cyclohexane-1,2-diisocyanate; cyclohexane-1,3-diisocyanate;cyclohexane-1,4-diisocyanate; methyl-cyclohexylene diisocyanate (HTDI);2,4-methylcyclohexane diisocyanate; 2,6-methylcyclohexane diisocyanate;4,4′-dicyclohexyl diisocyanate; 2,4′-dicyclohexyl diisocyanate;1,3,5-cyclohexane triisocyanate; isocyanatomethylcyclohexane isocyanate;1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane;isocyanatoethylcyclohexane isocyanate; bis(isocyanatomethyl)-cyclohexanediisocyanate; 4,4′-bis(isocyanatomethyl)dicyclohexane;2,4′-bis(isocyanatomethyl)dicyclohexane; isophoronediisocyanate (IPDI);triisocyanate of HDI; triisocyanate of 2,2,4-trimethyl-1,6-hexanediisocyanate (TMDI); 4,4′-docyclohexylmethane diisocyanate (H₁₂MDI);2,4-hexahydrotoluene diisocyanate; 2,6-hexahydrotoluene diisocyanate;aromatic aliphatic isocyanate, such as 1,2-, 1,3-, and 1,4-xylenediisocyanate; meta-tetramethylxylene diisocyanate (m-TMXDI);para-tetramethylxylene diisocyanate (p-TMXDI); trimerized isocyanurateof any polyisocyanate, such as isocyanurate of toluene diisocyanate,trimer of diphenylmethane diisocyanate, trimer of tetramethylxylenediisocyanate, isocyanurate of hexamethylene diisocyanate, isocyanurateof isophorone diisocyanate, and mixtures thereof; dimerized uredione ofany polyisocyanate, such as uretdione of toluene diisocyanate, uretdioneof hexamethylene diisocyanate, and mixtures thereof, modifiedpolyisocyanate derived from the above isocyanates and polyisocyanates;and mixtures thereof. In one embodiment, the saturated diisocyanatesinclude isophoronediisocyanate (IPDI), 4,4′-dicyclohexylmethanediisocyanate (H₁₂MDI), 1,6-hexamethylene diisocyanate (HDI), or acombination thereof.

The number of unreacted NCO groups in the polyurethane prepolymer may bevaried to control such factors as the speed of the reaction, theresultant hardness of the composition, and the like. For instance, thenumber of unreacted NCO groups in the polyurethane prepolymer ofisocyanate and polyol may be less than about 14 percent. In oneembodiment, the polyurethane prepolymer has from about 5 percent toabout 11 percent unreacted NCO groups, and even more preferably has fromabout 6 to about 9.5 percent unreacted NCO groups. In one embodiment,the percentage of unreacted NCO groups is about 3 percent to about 9percent. Alternatively, the percentage of unreacted NCO groups in thepolyurethane polymer may be about 7.5 percent or less, and morepreferably, about 7 percent or less. In another embodiment, theunreacted NCO content is from about 2.5 percent to about 7.5 percent,and more preferably from about 4 percent to about 6.5 percent.

Unsaturated diisocyanates, i.e., aromatic compounds, may also be usedwith the present invention, although the use of unsaturated compounds inthe prepolymer is preferably coupled with the use of a light stabilizeror pigment as discussed below. Examples of unsaturated diisocyanatesinclude, but are not limited to, substituted and isomeric mixturesincluding 2,2′-, 2,4′-, and 4,4′-diphenylmethane diisocyanate (MDI),3,3′-dimethyl-4,4′-biphenyl diisocyanate (TODI), toluene diisocyanate(TDI), polymeric MDI, carbodimide-modified liquid 4,4′-diphenylmethanediisocyanate, para-phenylene diisocyanate (PPDI), meta-phenylenediisocyanate (MPDI), triphenylmethane-4,4′-, andtriphenylmethane-4,4″-triisocyanate, napthylene-1,5,-diisocyanate,2,4′-, 4,4′-, and 2,2-biphenyl diisocyanate, polyphenyl polymethylenepolyisocyanate (PMDI), and mixtures thereof.

Polyol Component

Any saturated polyol available to one of ordinary skill in the art issuitable for use in the polyurethane prepolymer. Exemplary polyolsinclude, but are not limited to, polyether polyols, polycaprolactonepolyols, polyester polyols, polycarbonate polyols, hydrocarbon polyols,and mixtures thereof. Suitable saturated polyether polyols for use inthe present invention include, but are not limited to,polytetramethylene ether glycol (PTMEG); copolymer of polytetramethyleneether glycol and 2-methyl-1,4-butane diol (PTG-L);poly(oxyethylene)glycol; poly(oxypropylene)glycol; poly(ethylene oxidecapped oxypropylene)glycol; and mixtures thereof.

Saturated polycaprolactone polyols include, but not limited to,diethylene glycol initiated polycaprolactone; propylene glycol initiatedpolycaprolactone; 1,4-butanediol initiated polycaprolactone; trimethylolpropane initiated polycaprolactone; neopentyl glycol initiatedpolycaprolactone; 1,6-hexanediol initiated polycaprolactone;polytetramethylene ether glycol (PTMEG) initiated polycaprolactone;ethylene glycol initiated polycaprolactone; dipropylene glycol initiatedpolycaprolactone; and mixtures thereof.

Suitable saturated polyester polyols include, but not limited to,polyethylene adipate glycol; polyethylene propylene adipate glycol;polybutylene adipate glycol; polyethylene butylene adipate glycol;polyhexamethylene adipate glycol; polyhexamethylene butylene adipateglycol; and mixtures thereof. An example of a polycarbonate polyol thatmay be used with the present invention includes, but is not limited to,poly(hexamethylene carbonate) glycol.

Hydrocarbon polyols include, but not limited to, hydroxy-terminatedliquid isoprene rubber (LIR), hydroxy-terminated polybutadiene polyol,saturated hydroxy-terminated hydrocarbon polyols, and mixtures thereof.Other aliphatic polyols that may be used to form the prepolymer of theinvention include, but not limited to, glycerols; castor oil and itsderivatives; Kraton polyols; acrylic polyols; acid functionalizedpolyols based on a carboxylic, sulfonic, or phosphoric acid group; dimeralcohols converted from the saturated dimerized fatty acid; and mixturesthereof.

When formed, polyurethane prepolymers may contain about 10 percent toabout 20 percent by weight of the prepolymer of free isocyanate monomer.Thus, in one embodiment, the polyurethane prepolymer may be stripped ofthe free isocyanate monomer. For example, after stripping, theprepolymer may contain about 1 percent or less free isocyanate monomer.In another embodiment, the prepolymer contains about 0.5 percent byweight or less of free isocyanate monomer.

The polyurethane prepolymer may be formed with a single curing agent ora blend or mixture of curing agents. The curing agent of the inventionis preferably modified with a freezing point depressing agent asdiscussed above.

Curative

Saturated curatives for use with the present invention include, but arenot limited to, hydroxy terminated curing agents, amine-terminatedcuring agents, and mixtures thereof. Depending on the type of curingagent used, the polyurethane composition may be thermoplastic orthermoset in nature. For example, polyurethanes prepolymers cured with adiol or secondary diamine with 1:1 stoichiometry are thermoplastic innature. Thermoset polyurethanes, on the other hand, are generallyproduced from a prepolymer cured with a primary diamine orpolyfunctional glycol.

In addition, the type of curing agent used determines whether thepolyurethane composition is polyurethane-urethane or polyurethane-urea.For example, a polyurethane prepolymer cured with a hydroxy-terminatedcuring agent is polyurethane-urethane because any excess isocyanategroups will react with the hydroxyl groups of the curing agent to createmore urethane linkages. In contrast, if an amine-terminated curing agentis used with the polyurethane prepolymer, the excess isocyanate groupswill react with the amine groups of the amine-terminated curing agent tocreate urea linkages.

Suitable saturated hydroxy-terminated curing agents include, but are notlimited to, ethylene glycol; diethylene glycol; polyethylene glycol;propylene glycol; 2-methyl-1,3-propanediol; 2-methyl-1,4-butanediol;dipropylene glycol; polypropylene glycol; 1,2-butanediol;1,3-butanediol; 1,4-butanediol; 2,3-butanediol;2,3-dimethyl-2,3-butanediol; trimethylolpropane; triisopropanolamine;diethylene glycol di-(aminopropyl)ether; 1,5-pentanediol;1,6-hexanediol; glycerol; 1,3-bis-(2-hydroxyethoxy)cyclohexane;1,4-cyclohexyldimethylol;1,3-bis-[2-(2-hydroxyethoxy)ethoxy]cyclohexane;1,3-bis-{2-[2-(2-hydroxyethoxy)ethoxy]ethoxy}cyclohexane;polytetramethylene ether glycol having molecular weight ranging fromabout 250 to about 3900; and mixtures thereof. In one embodiment, thehydroxy-terminated curing agent has a molecular weight of at least 50.In another embodiment, the molecular weight of the hydroxy-terminatedcuring agent is about 2000 or less. In yet another embodiment, thehydroxy-terminated curing agent has a molecular weight of about 250 toabout 3900. It should be understood that molecular weight, as usedherein, is the absolute weight average molecular weight and would beunderstood as such by one of ordinary skill in the art.

Suitable saturated amine-terminated curing agents include, but are notlimited to, ethylene diamine; hexamethylene diamine;1-methyl-2,6-cyclohexyl diamine; tetrahydroxypropylene ethylene diamine;2,2,4- and 2,4,4-trimethyl-1,6-hexanediamine;4,4′-bis-(sec-butylamino)-dicyclohexylmethane;1,4-bis-(sec-butylamino)-cyclohexane;1,2-bis-(sec-butylamino)-cyclohexane; derivatives of4,4′-bis-(sec-butylamino)-dicyclohexylmethane; 4,4′-dicyclohexylmethanediamine; 1,4-cyclohexane-bis-(methylamine);1,3-cyclohexane-bis-(methylamine); diethylene glycoldi-(aminopropyl)ether; N,N,N′,N′-tetrakis (2-hydroxypropyl)-ethylenediamine; 2-methylpentamethylene-diamine; diaminocyclohexane; diethylenetriamine; triethylene tetramine; tetraethylene pentamine; propylenediamine; dipropylene triamine; 1,3-diaminopropane; dimethylaminopropylamine; diethylamino propylamine; imido-bis-propylamine;monoethanolamine, diethanolamine; triethanolamine; monoisopropanolamine,diisopropanolamine; triisopropanolamine; isophoronediamine; and mixturesthereof. In one embodiment, the amine-curing agent has a molecularweight of about 64 or greater. In another embodiment, the molecularweight of the amine-curing agent is about 2000 or less.

Polyurea Composition

The compositions of the invention may also be polyurea-based, which aredistinctly different from polyurethane compositions, but also result indesirable aerodynamic and aesthetic characteristics when used in golfball components. The polyurea-based compositions are preferablysaturated in nature.

Without being bound to any particular theory, it is now believed thatsubstitution of the long chain polyol segment in the polyurethaneprepolymer with a long chain polyamine oligomer soft segment to form apolyurea prepolymer, improves shear, cut, and resiliency, as well asadhesion to other components. Thus, the polyurea compositions of thisinvention may be formed from the reaction product of an isocyanate andpolyamine prepolymer crosslinked with a curing agent. For example,polyurea-based compositions of the invention may be prepared from atleast one isocyanate, at least one polyether amine, and at least onediol curing agent or at least one diamine curing agent.

Polyamine Component

Any polyamine available to one of ordinary skill in the art is suitablefor use in the polyurea prepolymer. Polyether amines are particularlysuitable for use in the prepolymer. As used herein, “polyether amines”refer to at least polyoxyalkyleneamines containing primary amino groupsattached to the terminus of a polyether backbone. Due to the rapidreaction of isocyanate and amine, and the insolubility of many ureaproducts, however, the selection of diamines and polyether amines islimited to those allowing the successful formation of the polyureaprepolymers. In one embodiment, the polyether backbone is based ontetramethylene, propylene, ethylene, trimethylolpropane, glycerin, andmixtures thereof.

Suitable polyether amines include, but are not limited to,methyldiethanolamine; polyoxyalkylenediamines such as,polytetramethylene ether diamines, polyoxypropylenetriamine, andpolyoxypropylene diamines; poly(ethylene oxide capped oxypropylene)etherdiamines; propylene oxide-based triamines; triethyleneglycoldiamines;trimethylolpropane-based triamines; glycerin-based triamines; andmixtures thereof. In one embodiment, the polyether amine used to formthe prepolymer is Jeffamine D2000 (manufactured by Huntsman Corporationof Austin, Tex.).

The molecular weight of the polyether amine for use in the polyureaprepolymer may range from about 100 to about 5000. As used herein, theterm “about” is used in connection with one or more numbers or numericalranges, should be understood to refer to all such numbers, including allnumbers in a range. In one embodiment, the polyether amine molecularweight is about 200 or greater, preferably about 230 or greater. Inanother embodiment, the molecular weight of the polyether amine is about4000 or less. In yet another embodiment, the molecular weight of thepolyether amine is about 600 or greater. In still another embodiment,the molecular weight of the polyether amine is about 3000 or less. Inyet another embodiment, the molecular weight of the polyether amine isbetween about 1000 and about 3000, and more preferably is between about1500 to about 2500. Because lower molecular weight polyether amines maybe prone to forming solid polyureas, a higher molecular weight oligomer,such as Jeffamine D2000, is preferred.

In one embodiment, the polyether amine has the generic structure:

wherein the repeating unit x has a value ranging from about 1 to about70. Even more preferably, the repeating unit may be from about 5 toabout 50, and even more preferably is from about 12 to about 35.

In another embodiment, the polyether amine has the generic structure:

wherein the repeating units x and z have combined values from about 3.6to about 8 and the repeating unit y has a value ranging from about 9 toabout 50, and wherein R is —(CH₂)_(a)—, where “a” may be a repeatingunit ranging from about 1 to about 10.

In yet another embodiment, the polyether amine has the genericstructure:H₂N—(R)—O—(R)—O—(R)—NH₂wherein R is —(CH₂)_(a)—, and “a” may be a repeating unit ranging fromabout 1 to about 10.

As briefly discussed above, some amines may be unsuitable for reactionwith the isocyanate because of the rapid reaction between the twocomponents. In particular, shorter chain amines are fast reacting. Inone embodiment, however, a hindered secondary diamine may be suitablefor use in the prepolymer. Without being bound to any particular theory,it is believed that an amine with a high level of stearic hindrance,e.g., a tertiary butyl group on the nitrogen atom, has a slower reactionrate than an amine with no hindrance or a low level of hindrance. Forexample, 4,4′-bis-(sec-butylamino)-dicyclohexylmethane (Clearlink 1000)may be suitable for use in combination with an isocyanate to form thepolyurea prepolymer.

Isocyanate Component

Any isocyanate available to one of ordinary skill in the art is suitablefor use in the polyurea prepolymer. Isocyanates for use with the presentinvention include aliphatic, cycloaliphatic, araliphatic, aromatic, anyderivatives thereof, and combinations of these compounds having two ormore isocyanate (NCO) groups per molecule. The isocyanates may beorganic polyisocyanate-terminated prepolymers. The isocyanate-containingreactable component may also include any isocyanate-functional monomer,dimer, trimer, or multimeric adduct thereof, prepolymer,quasi-prepolymer, or mixtures thereof. Isocyanate-functional compoundsmay include monoisocyanates or polyisocyanates that include anyisocyanate functionality of two or more.

Suitable isocyanate-containing components include diisocyanates havingthe generic structure: O═C═N—R—N═C═O, where R is preferably a cyclic,aromatic, or linear or branched hydrocarbon moiety containing from about1 to about 20 carbon atoms. The diisocyanate may also contain one ormore cyclic groups or one or more phenyl groups. When multiple cyclic oraromatic groups are present, linear and/or branched hydrocarbonscontaining from about 1 to about 10 carbon atoms can be present asspacers between the cyclic or aromatic groups. In some cases, the cyclicor aromatic group(s) may be substituted at the 2-, 3-, and/or4-positions, or at the ortho-, meta-, and/or para-positions,respectively. Substituted groups may include, but are not limited to,halogens, primary, secondary, or tertiary hydrocarbon groups, or amixture thereof.

Examples of diisocyanates that can be used with the present inventioninclude, but are not limited to, substituted and isomeric mixturesincluding 2,2′-, 2,4′-, and 4,4′-diphenylmethane diisocyanate (MDI);3,3′-dimethyl-4,4′-biphenylene diisocyanate (TODI); toluene diisocyanate(TDI); polymeric MDI; carbodiimide-modified liquid 4,4′-diphenylmethanediisocyanate; para-phenylene diisocyanate (PPDI); meta-phenylenediisocyanate (MPDI); triphenyl methane-4,4′- and triphenylmethane-4,4″-triisocyanate; naphthylene-1,5-diisocyanate; 2,4′-, 4,4′-,and 2,2-biphenyl diisocyanate; polyphenyl polymethylene polyisocyanate(PMDI); mixtures of MDI and PMDI; mixtures of PMDI and TDI; ethylenediisocyanate; propylene-1,2-diisocyanate;tetramethylene-1,2-diisocyanate; tetramethylene-1,3-diisocyanate;tetramethylene-1,4-diisocyanate; 1,6-hexamethylene-diisocyanate (HDI);octamethylene diisocyanate; decamethylene diisocyanate;2,2,4-trimethylhexamethylene diisocyanate; 2,4,4-trimethylhexamethylenediisocyanate; dodecane-1,12-diisocyanate; cyclobutane-1,3-diisocyanate;cyclohexane-1,2-diisocyanate; cyclohexane-1,3-diisocyanate;cyclohexane-1,4-diisocyanate; methyl-cyclohexylene diisocyanate (HTDI);2,4-methylcyclohexane diisocyanate; 2,6-methylcyclohexane diisocyanate;4,4′-dicyclohexyl diisocyanate; 2,4′-dicyclohexyl diisocyanate;1,3,5-cyclohexane triisocyanate; isocyanatomethylcyclohexane isocyanate;1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane;isocyanatoethylcyclohexane isocyanate; bis(isocyanatomethyl)-cyclohexanediisocyanate; 4,4′-bis(isocyanatomethyl)dicyclohexane;2,4′-bis(isocyanatomethyl)dicyclohexane; isophorone diisocyanate (IPDI);triisocyanate of HDI; triisocyanate of 2,2,4-trimethyl-1,6-hexanediisocyanate (TMDI); 4,4′-dicyclohexylmethane diisocyanate (H₁₂MDI);2,4-hexahydrotoluene diisocyanate; 2,6-hexahydrotoluene diisocyanate;1,2-, 1,3-, and 1,4-phenylene diisocyanate; aromatic aliphaticisocyanate, such as 1,2-, 1,3-, and 1,4-xylene diisocyanate;meta-tetramethylxylene diisocyanate (m-TMXDI); para-tetramethylxylenediisocyanate (p-TMXDI); trimerized isocyanurate of any polyisocyanate,such as isocyanurate of toluene diisocyanate, trimer of diphenylmethanediisocyanate, trimer of tetramethylxylene diisocyanate, isocyanurate ofhexamethylene diisocyanate, isocyanurate of isophorone diisocyanate, andmixtures thereof; dimerized uredione of any polyisocyanate, such asuretdione of toluene diisocyanate, uretdione of hexamethylenediisocyanate, and mixtures thereof; modified polyisocyanate derived fromthe above isocyanates and polyisocyanates; and mixtures thereof.

Examples of saturated diisocyanates that can be used with the presentinvention include, but are not limited to, ethylene diisocyanate;propylene-1,2-diisocyanate; tetramethylene diisocyanate;tetramethylene-1,4-diisocyanate; 1,6-hexamethylene-diisocyanate (HDI);octamethylene diisocyanate; decamethylene diisocyanate;2,2,4-trimethylhexamethylene diisocyanate; 2,4,4-trimethylhexamethylenediisocyanate; dodecane-1,12-diisocyanate; cyclobutane-1,3-diisocyanate;cyclohexane-1,2-diisocyanate; cyclohexane-1,3-diisocyanate;cyclohexane-1,4-diisocyanate; methyl-cyclohexylene diisocyanate (HTDI);2,4-methylcyclohexane diisocyanate; 2,6-methylcyclohexane diisocyanate;4,4′-dicyclohexyl diisocyanate; 2,4′-dicyclohexyl diisocyanate;1,3,5-cyclohexane triisocyanate; isocyanatomethylcyclohexane isocyanate;1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane;isocyanatoethylcyclohexane isocyanate; bis(isocyanatomethyl)-cyclohexanediisocyanate; 4,4′-bis(isocyanatomethyl)dicyclohexane;2,4′-bis(isocyanatomethyl)dicyclohexane; isophorone diisocyanate (IPDI);triisocyanate of HDI; triisocyanate of 2,2,4-trimethyl-1,6-hexanediisocyanate (TMDI); 4,4′-dicyclohexylmethane diisocyanate (H₁₂MDI);2,4-hexahydrotoluene diisocyanate; 2,6-hexahydrotoluene diisocyanate;and mixtures thereof. Aromatic aliphatic isocyanates may also be used toform light stable materials. Examples of such isocyanates include 1,2-,1,3-, and 1,4-xylene diisocyanate; meta-tetramethylxylene diisocyanate(m-TMXDI); para-tetramethylxylene diisocyanate (p-TMXDI); trimerizedisocyanurate of any polyisocyanate, such as isocyanurate of toluenediisocyanate, trimer of diphenylmethane diisocyanate, trimer oftetramethylxylene diisocyanate, isocyanurate of hexamethylenediisocyanate, isocyanurate of isophorone diisocyanate, and mixturesthereof; dimerized uredione of any polyisocyanate, such as uretdione oftoluene diisocyanate, uretdione of hexamethylene diisocyanate, andmixtures thereof; modified polyisocyanate derived from the aboveisocyanates and polyisocyanates; and mixtures thereof. In addition, thearomatic aliphatic isocyanates may be mixed with any of the saturatedisocyanates listed above for the purposes of this invention.

The number of unreacted NCO groups in the polyurea prepolymer ofisocyanate and polyether amine may be varied to control such factors asthe speed of the reaction, the resultant hardness of the composition,and the like. For instance, the number of unreacted NCO groups in thepolyurea prepolymer of isocyanate and polyether amine may be less thanabout 14 percent. In one embodiment, the polyurea prepolymer has fromabout 5 percent to about 11 percent unreacted NCO groups, and even morepreferably has from about 6 to about 9.5 percent unreacted NCO groups.In one embodiment, the percentage of unreacted NCO groups is about 3percent to about 9 percent. Alternatively, the percentage of unreactedNCO groups in the polyurea prepolymer may be about 7.5 percent or less,and more preferably, about 7 percent or less. In another embodiment, theunreacted NCO content is from about 2.5 percent to about 7.5 percent,and more preferably from about 4 percent to about 6.5 percent.

When formed, polyurea prepolymers may contain about 10 percent to about20 percent by weight of the prepolymer of free isocyanate monomer. Thus,in one embodiment, the polyurea prepolymer may be stripped of the freeisocyanate monomer. For example, after stripping, the prepolymer maycontain about 1 percent or less free isocyanate monomer. In anotherembodiment, the prepolymer contains about 0.5 percent by weight or lessof free isocyanate monomer.

The polyether amine may be blended with additional polyols to formulatecopolymers that are reacted with excess isocyanate to form the polyureaprepolymer. In one embodiment, less than about 30 percent polyol byweight of the copolymer is blended with the saturated polyether amine.In another embodiment, less than about 20 percent polyol by weight ofthe copolymer, preferably less than about 15 percent by weight of thecopolymer, is blended with the polyether amine. The polyols listed abovewith respect to the polyurethane prepolymer, e.g., polyether polyols,polycaprolactone polyols, polyester polyols, polycarbonate polyols,hydrocarbon polyols, other polyols, and mixtures thereof, are alsosuitable for blending with the polyether amine. The molecular weight ofthese polymers may be from about 200 to about 4000, but also may be fromabout 1000 to about 3000, and more preferably are from about 1500 toabout 2500.

Curative

The polyurea composition can be formed by crosslinking the polyureaprepolymer with a single curing agent or a blend of curing agents. Thecuring agent of the invention is preferably an amine-terminated curingagent, more preferably a secondary diamine curing agent so that thecomposition contains only urea linkages. In one embodiment, theamine-terminated curing agent may have a molecular weight of about 64 orgreater. In another embodiment, the molecular weight of the amine-curingagent is about 2000 or less. As discussed above, certainamine-terminated curing agents may be modified with a compatibleamine-terminated freezing point depressing agent or mixture ofcompatible freezing point depressing agents.

Suitable amine-terminated curing agents include, but are not limited to,ethylene diamine; hexamethylene diamine; 1-methyl-2,6-cyclohexyldiamine; tetrahydroxypropylene ethylene diamine; 2,2,4- and2,4,4-trimethyl-1,6-hexanediamine;4,4′-bis-(sec-butylamino)-dicyclohexylmethane;1,4-bis-(sec-butylamino)-cyclohexane;1,2-bis-(sec-butylamino)-cyclohexane; derivatives of4,4′-bis-(sec-butylamino)-dicyclohexylmethane; 4,4′-dicyclohexylmethanediamine; 1,4-cyclohexane-bis-(methylamine);1,3-cyclohexane-bis-(methylamine); diethylene glycoldi-(aminopropyl)ether; 2-methylpentamethylene-diamine;diaminocyclohexane; diethylene triamine; triethylene tetramine;tetraethylene pentamine; propylene diamine; 1,3-diaminopropane;dimethylamino propylamine; diethylamino propylamine; dipropylenetriamine; imido-bis-propylamine; monoethanolamine, diethanolamine;triethanolamine; monoisopropanolamine, diisopropanolamine;isophoronediamine; 4,4′-methylenebis-(2-chloroaniline);3,5;dimethylthio-2,4-toluenediamine;3,5-dimethylthio-2,6-toluenediamine; 3,5-diethylthio-2,4-toluenediamine;3,5;diethylthio-2,6-toluenediamine;4,4′-bis-(sec-butylamino)-diphenylmethane and derivatives thereof;1,4-bis-(sec-butylamino)-benzene; 1,2-bis-(sec-butylamino)-benzene;N,N′-dialkylamino-diphenylmethane; N,N,N′,N′-tetrakis(2-hydroxypropyl)ethylene diamine;trimethyleneglycol-di-p-aminobenzoate;polytetramethyleneoxide-di-p-aminobenzoate;4,4′-methylenebis-(3-chloro-2,6-diethyleneaniline);4,4′-methylenebis-(2,6-diethylaniline); meta-phenylenediamine;paraphenylenediamine; and mixtures thereof. In one embodiment, theamine-terminated curing agent is4,4′-bis-(sec-butylamino)-dicyclohexylmethane.

Suitable saturated amine-terminated curing agents include, but are notlimited to, ethylene diamine; hexamethylene diamine;1-methyl-2,6-cyclohexyl diamine; tetrahydroxypropylene ethylene diamine;2,2,4- and 2,4,4-trimethyl-1,6-hexanediamine;4,4′-bis-(sec-butylamino)-dicyclohexylmethane;1,4-bis-(sec-butylamino)-cyclohexane;1,2-bis-(sec-butylamino)-cyclohexane; derivatives of4,4′-bis-(sec-butylamino)-dicyclohexylmethane; 4,4′-dicyclohexylmethanediamine; 4,4′-methylenebis-(2,6-diethylaminocyclohexane;1,4-cyclohexane-bis-(methylamine); 1,3-cyclohexane-bis-(methylamine);diethylene glycol di-(aminopropyl)ether; 2-methylpentamethylene-diamine;diaminocyclohexane; diethylene triamine; triethylene tetramine;tetraethylene pentamine; propylene diamine; 1,3-diaminopropane;dimethylamino propylamine; diethylamino propylamine;imido-bis-propylamine; monoethanolamine, diethanolamine;triethanolamine; monoisopropanolamine, diisopropanolamine;isophoronediamine; triisopropanolamine; and mixtures thereof. Inaddition, any of the polyether amines listed above may be used as curingagents to react with the polyurea prepolymers.

In addition, the polyurea prepolymer may be cured with a singlehydroxy-terminated curing agent or a mixture of hydroxy-terminatedcuring agents. Once a hydroxy-terminated curing agent is used, however,the excess isocyanate in the polyurea prepolymer reacts with thehydroxyl groups in the curing agent and forms urethane linkages, whichresults in a composition that is no longer pure polyurea, but instead apolyurea-urethane composition. The hydroxy-terminated curing agent ispreferably modified with a hydroxy-terminated freezing point depressingagent as discussed above.

Suitable hydroxy-terminated curing agents include, but are not limitedto, ethylene glycol; diethylene glycol; polyethylene glycol; propyleneglycol; 2-methyl-1,3-propanediol; 2,-methyl-1,4-butanediol; dipropyleneglycol; polypropylene glycol; 1,2-butanediol; 1,3-butanediol;1,4-butanediol; 2,3-butanediol; 2,3-dimethyl-2,3-butanediol;trimethylolpropane; cyclohexyldimethylol; triisopropanolamine;tetra-(2-hydroxypropyl)-ethylene diamine; diethylene glycoldi-(aminopropyl)ether; 1,5-pentanediol; 1,6-hexanediol;1,3-bis-(2-hydroxyethoxy)cyclohexane; 1,4-cyclohexyldimethylol;1,3-bis-[2-(2-hydroxyethoxy)ethoxy]cyclohexane;1,3-bis-{2-[2-(2-hydroxyethoxy)ethoxy]ethoxy}cyclohexane;trimethylolpropane; polytetramethylene ether glycol, preferably having amolecular weight ranging from about 250 to about 3900;resorcinol-di-(beat-hydroxyethyl)ether and its derivatives;hydroquinone-di-(beta-hydroxyethyl)ether and its derivatives;1,3-bis-(2-hydroxyethoxy)benzene;1,3-bis-[2-(2-hydroxyethoxy)ethoxy]benzene;N,N-bis(β-hydroxypropyl)aniline; 2-propanol-1,1′-phenylaminobis; andmixtures thereof. The hydroxy-terminated curing agent may have amolecular weight of at least about 50. In one embodiment, the molecularweight of the hydroxy-terminated curing agent is about 2000 or less.

Suitable saturated hydroxy-terminated curing agents include, but are notlimited to, ethylene glycol; diethylene glycol; polyethylene glycol;propylene glycol; 2-methyl-1,3-propanediol; 2,-methyl-1,4-butanediol;dipropylene glycol; polypropylene glycol; 1,2-butanediol;1,3-butanediol; 1,4-butanediol; 2,3-butanediol;2,3-dimethyl-2,3-butanediol; trimethylolpropane; cyclohexyldimethylol;triisopropanolamine; tetra-(2-hydroxypropyl)-ethylene diamine;diethylene glycol di-(aminopropyl)ether; 1,5-pentanediol;1,6-hexanediol; 1,3-bis-(2-hydroxyethoxy)cyclohexane;1,4-cyclohexyldimethylol;1,3-bis-[2-(2-hydroxyethoxy)ethoxy]cyclohexane;1,3-bis-{2-[2-(2-hydroxyethoxy)ethoxy]ethoxy}cyclohexane;trimethylolpropane; polytetramethylene ether glycol having molecularweight ranging from about 250 to about 3900; and mixtures thereof. Inone embodiment, the hydroxy-terminated curing agent has a molecularweight of at least 50. In another embodiment, the molecular weight ofthe hydroxy-terminated curing agent is about 2000 or less.

Both types of curing agents, i.e., hydroxy-terminated and aminecuratives, may include one or more saturated, unsaturated, aromatic, andcyclic groups. Additionally, the hydroxy-terminated and amine curativesmay include one or more halogen groups.

Skilled artisians are aware that the various properties of the golf balland golf ball components, e.g., hardness, may be controlled by adjustingthe ratio of prepolymer to curing agent, which is a function of the NCOcontent of the prepolymer and molecular weight of the curing agent. Forexample, the ratio of a polyurea prepolymer with 6 percent unreacted NCOgroups cured with 1,4-butanediol is 15.6:1, whereas the ratio of thesame prepolymer cured with 4,4′-bis-(sec-butylamino)-dicyclohexylmethane(Clearlink 1000) is 4.36:1. The ratio of prepolymer to curing agent forthe purposes of this invention is preferably from about 0.5:1 to about16:1.

Composition Additives

Additional materials conventionally included in polyurethane andpolyurea compositions may be added to the polyurethane and polyureaprepolymers, the modified curative blends, or the composite compositionsof the invention. These additional materials include, but are notlimited to, catalysts, wetting agents, coloring agents, opticalbrighteners, crosslinking agents, whitening agents such as TiO₂ and ZnO,UV absorbers, hindered amine light stabilizers, defoaming agents,processing aids, surfactants, and other conventional additives. Forexample, wetting additives may be added to the modified curative blendsof the invention to more effectively disperse the pigment(s). Suitablewetting agents are available from Byk-Chemle and Crompton Corporation,among others.

Antioxidants, stabilizers, softening agents, plasticizers, includinginternal and external plasticizers, impact modifiers, foaming agents,density-adjusting fillers, reinforcing materials, and compatibilizersmay also be added to any composition of the invention. Those of ordinaryskill in the art are aware of the purpose of these additives and theamounts that should be employed to fulfill those purposes.

Catalysts

A catalyst may also be employed to promote the reaction between theprepolymer and the curing agent for both the polyurethane and polyureacompositions. Suitable catalysts include, but are not limited to bismuthcatalyst; zinc octoate; stannous octoate; tin catalysts such asdi-butyltin dilaurate (DABCO® T-12 manufactured by Air Products andChemicals, Inc.), di-butyltin diacetate (DABCO® T-1); stannous octoate(DABCO® T-9); tin (II) chloride, tin (IV) chloride, di-butyltindimethoxide (FASCAT®-4211), dimethyl-bis[1-oxonedecyl)oxy]stannane(FORMEZ® UL-28), di-n-octyltin bis-isooctyl mercaptoacetate (FORMEZ®UL-29); amine catalysts such as triethylenediamine (DABCO® 33-LV),triethylamine, and tributylamine; organic acids such as oleic acid andacetic acid; delayed catalysts such as POLYCAT™ SA-1, POLYCAT™ SA-2,POLYCAT™, and the like; and mixtures thereof. In one embodiment, thecatalyst is di-butyltin dilaurate.

The catalyst is preferably added in an amount sufficient to catalyze thereaction of the components in the reactive mixture. In one embodiment,the catalyst is present in an amount from about 0.001 percent to about 5percent by weight of the composition. For example, when using a tincatalyst, such as di-butyltin dilaurate, the catalyst is preferablypresent in an amount from about 0.005 percent to about 1 percent. Inanother embodiment, the catalyst is present in an amount of about 0.05weight percent or greater. In another embodiment, the catalyst ispresent in an amount of about 0.5 weight percent or greater.

Use of low levels of tin catalysts, typically from about 0 to about 0.04weight percent of the total composition, requires high temperatures toachieve a suitable reaction rate, which may result in degradation of theprepolymer. Increasing the amount of catalysts to unconventional highlevels enables the reduction in process temperatures while retainingcomparable cure stages. Use of the higher catalyst level also allows themixing speeds to be reduced. Thus, in one embodiment, the tin catalystis present in an amount from about 0.01 percent to about 0.55 percent byweight of the composition. In another embodiment, about 0.05 percent toabout 0.4 percent of tin catalyst is present in the composition. In yetanother embodiment, the tin catalyst is present in an amount from about0.1 percent to about 0.25 percent.

Density-Adjusting Filler(s)

Fillers may be added to the polyurethane and polyurea compositions ofthe invention to affect rheological and mixing properties, the specificgravity (i.e., density-modifying fillers), the modulus, the tearstrength, reinforcement, and the like. The fillers are generallyinorganic, and suitable fillers include numerous metals, metal oxidesand salts, such as zinc oxide and tin oxide, as well as barium sulfate,zinc sulfate, calcium carbonate, zinc carbonate, barium carbonate, clay,tungsten, tungsten carbide, an array of silicas, regrind (recycled corematerial typically ground to about 30 mesh particle),high-Mooney-viscosity rubber regrind, and mixtures thereof.

For example, the compositions of the invention can be reinforced byblending with a wide range of density-adjusting fillers, e.g., ceramics,glass spheres (solid or hollow, and filled or unfilled), and fibers,inorganic particles, and metal particles, such as metal flakes, metallicpowders, oxides, and derivatives thereof, as is known to those withskill in the art. The selection of such filler(s) is dependent upon thetype of golf ball desired, i.e., one-piece, two-piece, multi-component,or wound, as will be more fully detailed below. Generally, the fillerwill be inorganic, having a density of greater than 4 g/cc, and will bepresent in amounts between about 5 and about 65 weight percent based onthe total weight of the polymer components included in the layer(s) inquestion. Examples of useful fillers include zinc oxide, barium sulfate,calcium oxide, calcium carbonate, and silica, as well as other knowncorresponding salts and oxides thereof.

Fillers may also be used to modify the weight of the core or at leastone additional layer for specialty balls, e.g., a lower weight ball ispreferred for a player having a low swing speed.

Blowing or Foaming Agent(s)

The compositions of the invention may be foamed by the addition of theat least one physical or chemical blowing or foaming agent. The use of afoamed polymer allows the golf ball designer to adjust the density ormass distribution of the ball to adjust the angular moment of inertia,and, thus, the spin rate and performance of the ball. Foamed materialsalso offer a potential cost savings due to the reduced use of polymericmaterial.

Blowing or foaming agents useful include, but are not limited to,organic blowing agents, such as azobisformamide; azobisisobutyronitrile;diazoaminobenzene; N,N-dimethyl-N,N-dinitroso terephthalamide;N,N-dinitrosopentamethylene-tetramine; benzenesulfonyl-hydrazide;benzene-1,3-disulfonyl hydrazide; diphenylsulfon-3-3, disulfonylhydrazide; 4,4′-oxybis benzene sulfonyl hydrazide; p-toluene sulfonylsemicarbizide; barium azodicarboxylate; butylamine nitrile; nitroureas;trihydrazino triazine; phenyl-methyl-uranthan; p-sulfonhydrazide;peroxides; and inorganic blowing agents such as ammonium bicarbonate andsodium bicarbonate. A gas, such as air, nitrogen, carbon dioxide, etc.,can also be injected into the composition during the injection moldingprocess.

Additionally, a foamed composition of the present invention may beformed by blending microspheres with the composition either during orbefore the molding process. Polymeric, ceramic, metal, and glassmicrospheres are useful in the invention, and may be solid or hollow andfilled or unfilled. In particular, microspheres up to about 1000micrometers in diameter are useful.

Either injection molding or compression molding may be used to form alayer or a core including a foamed polymeric material. For example, acomposition of the present invention can be thermoformed and, thus, canbe compression molded. For compression molded grafted metallocenecatalyzed polymer blend layers, half-shells may be made by injectionmolding a grafted metallocene catalyzed polymer blend in a conventionalhalf-shell mold or by compression molding sheets of foamed graftedmetallocene catalyzed polymer. The half-shells are placed about apreviously formed center or core, cover, or mantle layer, and theassembly is introduced into a compression molding machine, andcompression molded at about 250° F. to 400° F. The molded balls are thencooled while still in the mold, and finally removed when the layer ofgrafted metallocene catalyzed polymer blend is hard enough to be handledwithout deforming. Additional core, mantle, and cover layers are thenmolded onto the previously molded layers, as needed, until a completeball is formed.

Light Stabilizers

The compositions of the invention may contain at least one lightstabilizing component to prevent significant yellowing from unsaturatedcomponents contained therein. The use of a light stabilizer ispreferred, for instance, for compositions having a difference inyellowness (*Y) of about 15 or greater, but also may be added tocompositions having a difference in yellowness of from about 12 to about15. As used herein, light stabilizer may be understood to includehindered amine light stabilizers, ultraviolet (UV) absorbers, andantioxidants.

Suitable light stabilizers include, but are not limited to, TINUVIN®292, TINUVIN® 328, TINUVIN® 213, TINUVIN® 765, TINUVIN® 770 and TINUVIN®622. TINUVIN® products are available from Ciba-Geigy. In one embodiment,the light stabilizer is UV absorber TINUVIN® 328, which is useful witharomatic compounds. In another embodiment, hindered amine lightstabilizer TINUVIN® 765 is used with aromatic or aliphatic compounds. Inaddition, TINUVIN® 292 may also be used with the aromatic or aliphaticcompositions of the invention.

As discussed above, dyes, as well as optical brighteners and fluorescentpigments may also be included in the golf ball covers produced withpolymers formed according to the present invention. Such additionalingredients may be added in any amounts that will achieve their desiredpurpose.

As discussed, the compositions of the invention preferably include onlysaturated components because unsaturated components yellow over a periodof time. While saturated compositions are resistant to discoloration,they are not immune to deterioration in their mechanical properties uponweathering. Addition of UV absorbers and light stabilizers to any of theabove compositions may help to maintain the tensile strength,elongation, and color stability. The use of light stabilizing componentsalso may assist in preventing cover surface fractures due tophotodegredation. Thus, suitable NV absorbers and light stabilizers, aslisted above, may also be included in the saturated compositions of theinvention.

To further improve the shear resistance and heat resistance of theresulting polyurea elastomers, a multi-functional curing agent can beused to help improve cross-linking. In one embodiment of the presentinvention, the multi-functional curing agent is modified with acompatible freezing point depressing agent as detailed above. Forexample, a triol such as trimethylolpropane or a tetraol such asN,N,N′,N′-tetrakis(2-hydroxylpropyl)ethylenediamine may be added to thecomposition. In one embodiment, a primary diamine, such as3,3′-dimethyl-4,4′-diaminodicyclohexylmethane or4,4′-diaminodicyclohexylmethane is added to the polyurea composition.Useful triamine curing agents for improving the crosslinking of polyureaelastomers include, but are not limited to: propylene oxide-basedtriamines; trimethylolpropane-based triamines; glycerin-based triamines;N,N-bis{2-[(aminocarbonyl)amino]ethyl}-urea;N,N′,N″-tris(2-aminoethyl)-methanetriamine;N1-(5-aminopentyl)-1,2,6-hexanetriamine; 1,1,2-ethanetriamine;N,N′,N″-tris(3-aminopropyl)-methanetriamine;N1-(2-aminoethyl)-1,2,6-hexanetriamine;N1-(10-aminodecyl)-1,2,6-hexanetriamine; 1,9,18-octadecanetriamine;4,10,16,22-tetraazapentacosane-1,13,25-triamine;N1-{3-[[4-[(3-aminopropyl)amino]butyl]amino]propyl}-1,2,6-hexanetriamine;di-9-octadecenyl-(Z,Z)-1,2,3-propanetriamine; 1,4,8-octanetriamine;1,5,9-nonanetriamine; 1,9,10-octadecanetriamine; 1,4,7-heptanetriamine;1,5,10-decanetriamine; 1,8,17-heptadecanetriamine; 1,2,4-butanetriamine;propanetriamine; 1,3,5-pentanetriamine;N1-{3-[[4-[(3-aminopropyl)amino]butyl]amino]propyl}-1,2,6-hexanetriamine;N1-{4-[(3-aminopropyl)amino]butyl}-1,2,6-hexanetriamine;2,5-dimethyl-1,4,7-heptanetriamine;N1-(6-aminohexyl)-1,2,6-hexanetriamine;6-ethyl-3,9-dimethyl-3,6,9-undecanetriamine; 1,5,11-undecanetriamine;1,6,11-undecanetriamine; N,N-bis(aminomethyl)-methanediamine;N,N-bis(2-aminoethyl)-1,3-propanediamine; methanetriamine;N1-(2-aminoethyl)-N2-(3-aminopropyl)-1,2,5-pentanetriamine;N1-(2-aminoethyl)-1,2,6-hexanetriamine;2,6,11-trimethyl-2,6,11-dodecanetriamine; 1,1,3-propanetriamine;6-(aminomethyl)-1,4,9-nonanetriamine; 1,2,6-hexanetriamine;N2-(2-aminoethyl)-1,1,2-ethanetriamine; 1,3,6-hexanetriamine;N,N-bis(2-aminoethyl)-1,2-ethanediamine;3-(aminomethyl)-1,2,4-butanetriamine; 1,1,1-ethanetriamine;N1,N1-bis(2-aminoethyl)1,2-propanediamine; 1,2,3-propanetriamine;2-methyl-1,2,3-propanetriamine; and mixtures thereof.

Fragrance Components

Some materials used in the polyurethane or polyurea compositions of theinvention are odorous in nature or produce odors during reaction withother materials or with oxygen. For example, the odor of curativeEthacure 300 is attributed to dimethyl disulfide (DMDS) once the productreacts with oxygen. As used herein, a material or component is odorouswhen the odor threshold surpasses a threshold of 0.029 mg/m³ in air. Afragrance or masking component may be added to the compositions of theinvention to eliminate odors.

The fragrance component is preferably added in an amount of about 0.01percent to about 1.5 percent by weight of the composition. In oneembodiment, the fragrance component is added to the composition in anamount of about 0.03 percent or greater by weight of the composition. Inanother embodiment, the fragrance component is added to the compositionin an amount of about 1.2 percent or less by weight of the composition.In yet another embodiment, the fragrance component is added in an amountof about 0.5 percent to about 1 percent by weight of the composition.For example, an optimum loading of the fragrance component may be about0.08 percent by weight of the composition, but adding more may enhancethe effect is needed.

Suitable fragrance components include, but are not limited to, LongLasting Fragance Mask #59672, Long Lasting Fragance Mask #46064, LongLasting Fragance Mask #55248, Non-Descript Fragrance Mask #97779, Freshand Clean Fragrance Mask #88177, and Garden Fresh Fragrance Mask #87473,all of which are manufactured by Flavor and Fragrance Specialties ofMahwah, N.J. Other non-limiting examples of fragrance components thatmay be added to the compositions of the invention include benzaldehyde,benzyl benzoate, benzyl propionate, benzyl salicylate, benzyl alcohol,cinnamic aldehydes, natural and essential oils derived from botanicalsources, and mixtures thereof.

Composition Blends

The compositions of the invention preferably include from about 1percent to about 100 percent polyurethane or polyurea, depending onwhether the compositions are polyurethane-based or polyurea-based,however, the compositions may be blended with other materials. In oneembodiment, the composition contains about 10 percent to about 90percent of polyurethane or polyurea, preferably from about 10 percent toabout 75 percent polyurethane or polyurea, and contains about 90 percentto 10 percent, more preferably from about 90 percent to about 25 percentother polymers and/or other materials as described below.

Other polymeric materials suitable for blending with the compositions ofthe invention include castable thermoplastic or thermoset polyurethanes,cationic and anionic urethane ionomers and urethane epoxies,polyurethane/polyurea ionomers, epoxy resins, polyethylenes, polyamidesand polyesters, polycarbonates, polyacrylin, and mixtures thereof.Examples of suitable urethane ionomers are disclosed in U.S. Pat. No.5,692,974, the disclosure of which is hereby incorporated by referencein its entirety. Other examples of suitable polyurethanes are describedin U.S. Pat. No. 5,334,673, the entire disclosure of which isincorporated by reference herein. Examples of suitable polyureas used toform the polyurea ionomer listed above are discussed in U.S. Pat. No.5,484,870. In particular, the polyureas of U.S. Pat. No. 5,484,870 areprepared by reacting a polyisocyanate and a polyamine curing agent toyield polyurea, which are distinct from the polyureas of the presentinvention which are formed from a polyurea prepolymer and curing agent.Examples of suitable polyurethanes cured with epoxy group containingcuring agents are disclosed in U.S. Pat. No. 5,908,358. The disclosuresof the above patents are incorporated herein by reference in theirentirety. These examples are intended to be non-limiting examples ofblends to be used with the present invention.

Acid Functionalization of Compositions

The present invention also contemplates the acid functionalization ofthe polyurethane and polyurea compositions of the invention as disclosedin U.S. patent application Ser. No. 10/072,395, filed on Feb. 5, 2002,entitled “Golf Ball Compositions Comprising a Novel Acid FunctionalPolyurethane, Polyurea, or Copolymer Thereof”, which is incorporated byreference herein in its entirety. Without being bound to any particulartheory, it is believed that polyurethanes and polyurea including acidfunctional moieties or groups have improved adhesion to other componentsor layers. The acid functional group is preferably based on a sulfonicgroup (HSO₃), carboxylic group (HCO₂), phosphoric acid group (H₂PO₃), ora combination thereof. More than one type of acid functional group maybe incorporated into the polyurea or polyurethane.

In one embodiment, the acid functional polyurethane or polyurea isprepared from a prepolymer having acid functional moieties. The acidgroup(s) may be incorporated onto the isocyanate moiety or polyolcomponent when making a polyurethane composition. When making a polyureacomposition of the invention, the acid group(s) may be incorporated ontothe isocyanate or polyether amine component.

Suitable acid functional polyols for use in the polyurethanecompositions of the invention, along with reagents and methods used toderive such acid functional polyols, are disclosed in detail in U.S.Pat. Nos. 5,661,207 and 6,103,822, the disclosures of which areincorporated herein by reference in their entirety. In one embodiment,acid functional polyols for use in a polyurethane prepolymer includescarboxylated, sulfonated, or phosphonated derivatives of polyesterpolyols. Suitable acid functional polyols may have an acid number(calculated by dividing acid equivalent weight to 56,100) of at leastabout 10, preferably from about 20 to about 420, more preferably fromabout 25 to about 150, and most preferably from about 30 to about 75. Inaddition, the hydroxyl number (calculated by dividing hydroxylequivalent number to 56,100) of the polyols may be at least about 10,preferably from about 20 to about 840, and more preferably from about 20to about 175, and most preferably from about 50 to about 150. Thepolyols may also have a hydroxyl functionality (average number ofhydroxyl groups per polyol molecule) of at least about 1.8, preferablyfrom about 2 to about 4.

Suitable acid functional isocyanates include conventional isocyanateshaving an acid functional group that may be formed by reacting aisocyanate and an acid functional group containing compound as describedin U.S. Pat. Nos. 4,956,438 and 5,071,578, the disclosures of which areincorporated herein by reference in their entirety.

The acid group(s) may also be incorporated during a post-polymerizationreaction, wherein the acid functional group(s) is introduced or attachedto the polyurethane or polyurea. Moreover, the acid functional polyureaor polyurethanes made by way of copolymerization as described above maybe further incorporated with additional acid functional groups throughsuch post-polymerization reactions. Suitable agents to incorporate acidfunctional groups onto the polyurethane or polyurea and methods formaking are described in U.S. Pat. No. 6,207,784, the entire disclosureof which is incorporated by reference herein.

One of ordinary skill in the art would be aware of other ways to preparethe acid functional polyurea or polyurethane. For example, a combinationof the embodiments described above may be used as described in U.S. Pat.No. 5,661,207, the disclosure of which is incorporated by reference inits entirety herein.

The acid functional polyurethanes or polyurea may be partially or fullyneutralized with an organic or an inorganic metal base and/or a tertiaryamine to produce anionic polyurethanes/polyurea ionomers. The base maybe added during preparation of the prepolymer or as a separateneutralization step on the already polymerized acid functionalpolyurethane and polyurea. If these stages occur simultaneously, thebase is preferably present throughout all stages.

Suitable metal bases used for partial or total neutralization mayinclude compounds such as metal oxides, metal hydroxides, metalcarbonates, metal bicarbonates and metal acetates. The metal ions mayinclude, but are not be limited to, Group IA, IB, IIA, IIB, IIIA, IIIB,IVA, IVB, VA, VB, VIA, VIB, VIIB and VIIIB metal ions. Preferredmetallic ions of such bases include lithium, sodium, potassium,magnesium, zinc, calcium, manganese, aluminum, tungsten, zirconium,titanium and hafnium. The amines are preferably hindered organictertiary amines such as tributylamine, triethylamine, triethylenediamine, dimethyl cetylamine and similar compounds. Primary or secondaryamines may be used, preferably only if the neutralization step takesplace after the polymer is formed, because the amine hydrogen willreadily react with the isocyanate groups thereby interfering with thepolyurea or polyurethane polymerization. One of ordinary skill in theart is aware of additional appropriate chemicals for neutralization.

Golf Ball Core Layer(s)

The cores of the golf balls formed according to the invention may besolid, semi-solid, hollow, fluid-filled or powder-filled, one-piece ormulti-component cores. The term “semi-solid” as used herein refers to apaste, a gel, or the like. Any core material known to one of ordinaryskill in that art is suitable for use in the golf balls of theinvention. Suitable core materials include thermoset materials, such asrubber, styrene butadiene, polybutadiene, isoprene, polyisoprene,trans-isoprene, as well as thermoplastics such as ionomer resins,polyamides or polyesters, and thermoplastic and thermoset polyurethaneelastomers. As mentioned above, the polyurethane or polyureacompositions of the present invention may also be incorporated into anycomponent of a golf ball, including the core.

In one embodiment, the golf ball core is formed from a compositionincluding a base rubber (natural, synthetic, or a combination thereof),a crosslinking agent, and a filler. In another embodiment, the golf ballcore is formed from a reaction product that includes a cis-to-transcatalyst, a resilient polymer component having polybutadiene, a freeradical source, and optionally, a crosslinking agent, a filler, or both.Various combinations of polymers, cis-to-trans catalysts, fillers,crosslinkers, and a source of free radicals, such as those disclosed inco-pending and co-assigned U.S. patent application Ser. No. 10/190,705,entitled “Low Compression, Resilient Golf Balls With Rubber Core,” filedJul. 9, 2002, the entire disclosure of which is incorporated byreference herein, may be used to form the reaction product. Althoughthis polybutadiene reaction product is discussed in a section pertainingto core compositions, the present invention also contemplates the use ofthe reaction product to form at least a portion of any component of agolf ball.

Polybutadiene Component

To obtain a higher resilience and lower compression, a high-molecularweight polybutadiene with a cis-isomer content preferably greater thanabout 40 percent is converted to increase the percentage of trans-isomercontent at any point in the golf ball or portion thereof. In oneembodiment, the cis-isomer is present in an amount of greater than about70 percent, preferably greater than about 80 percent, and morepreferably greater than about 90 percent of the total polybutadienecontent. In still another embodiment, the cis-isomer is present in anamount of greater than about 95 percent, and more preferably greaterthan about 96 percent, of the total polybutadiene content.

A low amount of 1,2-polybutadiene isomer (“vinyl-polybutadiene”) isdesired in the initial polybutadiene, and the reaction product. In oneembodiment, the vinyl polybutadiene isomer content is less than about 7percent, preferably less than about 4 percent, and more preferably lessthan about 2 percent.

The polybutadiene material may have a molecular weight of greater thanabout 200,000. In one embodiment, the polybutadiene molecular weight isgreater than about 250,000, and more preferably from about 300,000 to500,000. In another embodiment, the polybutadiene molecular weight isabout 400,000 or greater. It is preferred that the polydispersity of thematerial is no greater than about 2, more preferably no greater than1.8, and even more preferably no greater than 1.6.

In one embodiment, the polybutadiene has a Mooney viscosity greater thanabout 20, preferably greater than about 30, and more preferably greaterthan about 40. Mooney viscosity is typically measured according to ASTMD-1646. In another embodiment, the Mooney viscosity of the polybutadieneis greater than about 35, and preferably greater than about 50. In oneembodiment, the Mooney viscosity of the unvulcanized polybutadiene isfrom about 40 to about 80. In another embodiment, the Mooney viscosityis from about 45 to about 60, more preferably from about 45 to about 55.

In one embodiment, the center composition includes at least one rubbermaterial having a resilience index of at least about 40. In anotherembodiment, the resilience index of the at least one rubber material isat least about 50.

Examples of desirable polybutadiene rubbers include BUNA® CB22 and BUNA®CB23, commercially available from Bayer of Akron, Ohio; UBEPOL® 360L andUBEPOL® 150L, commercially available from UBE Industries of Tokyo,Japan; and CARIFLEX® BCP820 and CARIFLEX® BCP824, commercially availablefrom Shell of Houston, Tex. If desired, the polybutadiene can also bemixed with other elastomers known in the art such as natural rubber,polyisoprene rubber and/or styrene-butadiene rubber in order to modifythe properties of the core.

Catalyst(s)

Without being bound by any particular theory, it is believed that thecis-to-trans catalyst component, in conjunction with the free radicalsource, acts to convert a percentage of the polybutadiene polymercomponent from the cis- to the trans-conformation. Thus, thecis-to-trans conversion prefereably includes the presence of acis-to-trans catalyst, such as an organosulfur or metal-containingorganosulfur compound, a substituted or unsubstituted aromatic organiccompound that does not contain sulfur or metal, an inorganic sulfidecompound, an aromatic organometallic compound, or mixtures thereof.

As used herein, “cis-to-trans catalyst” means any component or acombination thereof that will convert at least a portion of cis-isomerto trans-isomer at a given temperature. The cis-to-trans catalystcomponent may include one or more cis-to-trans catalysts describedherein, but typically includes at least one organosulfur component, aGroup VIA component, an inorganic sulfide, or a combination thereof. Inone embodiment, the cis-to-trans catalyst is a blend of an organosulfurcomponent and an inorganic sulfide component or a Group VIA component.

As used herein when referring to the invention, the term “organosulfurcompound(s)” or “organosulfur component(s),” refers to any compoundcontaining carbon, hydrogen, and sulfur. As used herein, the term“sulfur component” means a component that is elemental sulfur, polymericsulfur, or a combination thereof. It should be further understood that“elemental sulfur” refers to the ring structure of S₈ and that“polymeric sulfur” is a structure including at least one additionalsulfur relative to the elemental sulfur.

The cis-to-trans catalyst is typically present in an amount sufficientto produce the reaction product so as to increase thetrans-polybutadiene isomer content to contain from about 5 percent to 70percent trans-isomer polybutadiene based on the total resilient polymercomponent. It is preferred that the cis-to-trans catalyst is present inan amount sufficient to increase the trans-polybutadiene isomer contentat least about 15 percent, more preferably at least about 20 percent,and even more preferably at least about 25 percent.

Therefore, the cis-to-trans catalyst is preferably present in an amountfrom about 0.1 to about 25 parts per hundred of the total resilientpolymer component. As used herein, the term “parts per hundred”, alsoknown as “phr”, is defined as the number of parts by weight of aparticular component present in a mixture, relative to 100 parts byweight of the total polymer component. Mathematically, this can beexpressed as the weight of an ingredient divided by the total weight ofthe polymer, multiplied by a factor of 100. In one embodiment, thecis-to-trans catalyst is present in an amount from about 0.1 to about 12phr of the total resilient polymer component. In another embodiment, thecis-to-trans catalyst is present in an amount from about 0.1 to about 10phr of the total resilient polymer component. In yet another embodiment,the cis-to-trans catalyst is present in an amount from about 0.1 toabout 8 phr of the total resilient polymer component. In still anotherembodiment, the cis-to-trans catalyst is present in an amount from about0.1 to about 5 phr of the total resilient polymer component. The lowerend of the ranges stated above also may be increased if it is determinedthat 0.1 phr does not provide the desired amound of conversion. Forinstance, the amount of the cis-to-trans catalyst is present may beabout 0.5 or more, 0.75 or more, 1.0 or more, or even 1.5 or more.

Suitable organosulfur components for use in the invention include, butare not limited to, at least one of diphenyl disulfide; 4,4′-ditolyldisulfide; 2,2′-benzamido diphenyl disulfide;bis(2-aminophenyl)disulfide; bis(4-aminophenyl)disulfide;bis(3-aminophenyl)disulfide; 2,2′-bis(4-aminonaphthyl)disulfide;2,2′-bis(3-aminonaphthyl)disulfide; 2,2′-bis(4-aminonaphthyl)disulfide;2,2′-bis(5-aminonaphthyl)disulfide; 2,2′-bis(6-aminonaphthyl)disulfide;2,2′-bis(7-aminonaphthyl)disulfide; 2,2′-bis(8-aminonaphthyl)disulfide;1,1′-bis(2-aminonaphthyl)disulfide; 1,1′-bis(3-aminonaphthyl)disulfide;1,1′-bis(3-aminonaphthyl)disulfide; 1,1′-bis(4-aminonaphthyl)disulfide;1,1′-bis(5-aminonaphthyl)disulfide; 1,1′-bis(6-aminonaphthyl)disulfide;1,1′-bis(7-aminonaphthyl)disulfide; 1,1′-bis(8-aminonaphthyl)disulfide;1,2′-diamino-1,2′-dithiodinaphthalene;2,3′-diamino-1,2′-dithiodinaphthalene; bis(4-chlorophenyl)disulfide;bis(2-chlorophenyl)disulfide; bis(3-chlorophenyl)disulfide;bis(4-bromophenyl)disulfide; bis(2-bromophenyl)disulfide;bis(3-bromophenyl)disulfide; bis(4-fluorophenyl)disulfide;bis(4-iodophenyl)disulfide; bis(2,5-dichlorophenyl)disulfide;bis(3,5-dichlorophenyl)disulfide; bis (2,4-dichlorophenyl)disulfide;bis(2,6-dichlorophenyl)disulfide; bis(2,5-dibromophenyl)disulfide;bis(3,5-dibromophenyl)disulfide; bis(2-chloro-5-bromophenyl)disulfide;bis(2,4,6-trichlorophenyl)disulfide;bis(2,3,4,5,6-pentachlorophenyl)disulfide; bis(4-cyanophenyl)disulfide;bis(2-cyanophenyl)disulfide; bis(4-nitrophenyl)disulfide;bis(2-nitrophenyl)disulfide; 2,2′-dithiobenzoic ethyl;2,2′-dithiobenzoic methyl; 2,2′-dithiobenzoic acid; 4,4′-dithiobenzoicethyl; bis(4-acetylphenyl)disulfide; bis(2-acetylphenyl)disulfide;bis(4-formylphenyl)disulfide; bis(4carbamoylphenyl)disulfide;1,1′-dinaphthyl disulfide; 2,2′-dinaphthyl disulfide; 1,2′-dinaphthyldisulfide; 2,2′-bis(1-chlorodinaphthyl)disulfide;2,2′-bis(1-bromonaphthyl)disulfide; 1,1′-bis(2-chloronaphthyl)disulfide;2,2′-bis(1-cyanonaphtyl)disulfide; 2,2′-bis(1-acetylnaphthyl)disulfide;and the like; or a mixture thereof. Most preferred organosulfurcomponents include diphenyl disulfide, 4,4′-ditolyl disulfide, or amixture thereof, especially 4,4′-ditolyl disulfide.

In one embodiment, the at least one organosulfur component issubstantially free of metal. As used herein, the term “substantiallyfree of metal” means less than about 10 weight percent, preferably lessthan about 5 weight percent, more preferably less than about 3 weightpercent, even more preferably less than about 1 weight percent, and mostpreferably less than about 0.01 weight percent. Suitable substituted orunsubstituted aromatic organic components that do not include sulfur ora metal include, but are not limited to, diphenyl acetylene, azobenzene,or a mixture thereof. The aromatic organic group preferably ranges insize from C₆ to C₂₀, and more preferably from C₆ to C₁₀.

In one embodiment, the organosulfur cis-to-trans catalyst is present inthe reaction product in an amount from about 0.5 phr or greater. Inanother embodiment, the cis-to-trans catalyst including a organosulfurcomponent is present in the reaction product in an amount from about 0.6phr or greater. In yet another embodiment, the cis-to-trans catalystincluding a organosulfur component is present in the reaction product inan amount from about 1.0 phr or greater. In still another embodiment,the cis-to-trans catalyst including a organosulfur component is presentin the reaction product in an amount from about 2.0 phr or greater.

Suitable metal-containing organosulfur components include, but are notlimited to, cadmium, copper, lead, and tellurium analogs ofdiethyldithiocarbamate, diamyldithiocarbamate, anddimethyldithiocarbamate, or mixtures thereof. In one embodiment, themetal-containing organosulfur cis-to-trans catalyst is present in thereaction product in an amount from about 1.0 phr or greater. In anotherembodiment, the cis-to-trans catalyst including a Group VIA component ispresent in the reaction product in an amount from about 2.0 phr orgreater. In yet another embodiment, the cis-to-trans catalyst includinga Group VIA component is present in the reaction product in an amountfrom about 2.5 phr or greater. In still another embodiment, thecis-to-trans catalyst including a Group VIA component is present in thereaction product in an amount from about 3.0 phr or greater.

The organosulfur component may also be an halogenated organosulfurcompound. Halogenated organosulfur compounds include, but are notlimited to those having the following general formula:

where R₁–R₅ can be C₁–C₈ alkyl groups; halogen groups; thiol groups(—SH), carboxylated groups; sulfonated groups; and hydrogen; in anyorder; and also pentafluorothiophenol; 2-fluorothiophenol;3-fluorothiophenol; 4-fluorothiophenol; 2,3-fluorothiophenol;2,4-fluorothiophenol; 3,4-fluorothiophenol; 3,5-fluorothiophenol2,3,4-fluorothiophenol; 3,4,5-fluorothiophenol;2,3,4,5-tetrafluorothiophenol; 2,3,5,6-tetrafluorothiophenol;4-chlorotetrafluorothiophenol; pentachlorothiophenol;2-chlorothiophenol; 3-chlorothiophenol; 4-chlorothiophenol;2,3-chlorothiophenol; 2,4-chlorothiophenol; 3,4-chlorothiophenol;3,5-chlorothiophenol; 2,3,4-chlorothiophenol; 3,4,5-chlorothiophenol;2,3,4,5-tetrachlorothiophenol; 2,3,5,6-tetrachlorothiophenol;pentabromothiophenol; 2-bromothiophenol; 3-bromothiophenol;4-bromothiophenol; 2,3-bromothiophenol; 2,4-bromothiophenol;3,4-bromothiophenol; 3,5-bromothiophenol; 2,3,4-bromothiophenol;3,4,5-bromothiophenol; 2,3,4,5-tetrabromothiophenol;2,3,5,6-tetrabromothiophenol; pentaiodothiophenol; 2-iodothiophenol;3-iodothiophenol; 4-iodothiophenol; 2,3-iodothiophenol;2,4-iodothiophenol; 3,4-iodothiophenol; 3,5-iodothiophenol;2,3,4-iodothiophenol; 3,4,5-iodothiophenol; 2,3,4,5-tetraiodothiophenol;2,3,5,6-tetraiodothiophenol and; and their zinc salts. Preferably, thehalogenated organosulfur compound is pentachlorothiophenol, which iscommercially available in neat form or under the tradename STRUKTOL®, aclay-based carrier containing the sulfur compound pentachlorothiophenolloaded at 45 percent (correlating to 2.4 parts PCTP). STRUKTOL® iscommercially available from Struktol Company of America of Stow, Ohio.PCTP is commercially available in neat form from eChinachem of SanFrancisco, Calif. and in the salt form from eChinachem of San Francisco,Calif. Most preferably, the halogenated organosulfur compound is thezinc salt of pentachlorothiophenol, which is commercially available fromeChinachem of San Francisco, Calif. The halogenated organosulfurcompounds of the present invention are preferably present in an amountgreater than about 2.2 phr, more preferably between about 2.3 phr andabout 5 phr, and most preferably between about 2.3 and about 4 phr.

The cis-to-trans catalyst may also include a Group VIA component. Asused herein, the terms “Group VIA component” or “Group VIA element” meana component that includes a sulfur component, selenium, tellurium, or acombination thereof. Elemental sulfur and polymeric sulfur arecommercially available from, e.g., Elastochem, Inc. of Chardon, Ohio.Exemplary sulfur catalyst compounds include PB(RM-S)-80 elemental sulfurand PB(CRST)-65 polymeric sulfur, each of which is available fromElastochem, Inc. An exemplary tellurium catalyst under the tradenameTELLOY and an exemplary selenium catalyst under the tradename VANDEX areeach commercially available from RT Vanderbilt of Norwalk, Conn.

In one embodiment, the cis-to-trans catalyst including a Group VIAcomponent is present in the reaction product in an amount from about0.25 phr or greater. In another embodiment, the cis-to-trans catalystincluding a Group VIA component is present in the reaction product in anamount from about 0.5 phr or greater. In yet another embodiment, thecis-to-trans catalyst including a Group VIA component is present in thereaction product in an amount from about 1.0 phr or greater.

Suitable inorganic sulfide components include, but are not limited totitanium sulfide, manganese sulfide, and sulfide analogs of iron,calcium, cobalt, molybdenum, tungsten, copper, selenium, yttrium, zinc,tin, and bismuth. In one embodiment, the cis-to-trans catalyst includingan inorganic sulfide component is present in the reaction product in anamount from about 0.5 phr or greater. In another embodiment, thecis-to-trans catalyst including a Group VIA component is present in thereaction product in an amount from about 0.75 phr or greater. In yetanother embodiment, the cis-to-trans catalyst including a Group VIAcomponent is present in the reaction product in an amount from about 1.0phr or greater.

When a reaction product includes a blend of cis-to-trans catalystsincluding an organosulfur component and an inorganic sulfide component,the organosulfur component is preferably present in an amount from about0.5 or greater, preferably 1.0 or greater, and more preferably about 1.5or greater and the inorganic sulfide component is preferably present inan amount from about 0.5 phr or greater, preferably 0.75 phr or greater,and more preferably about 1.0 phr or greater.

A substituted or unsubstituted aromatic organic compound may also beincluded in the cis-to-trans catalyst. In one embodiment, the aromaticorganic compound is substantially free of metal. Suitable substituted orunsubstituted aromatic organic components include, but are not limitedto, components having the formula (R₁)_(x)—R₃-M-R₄—(R₂)_(y), wherein R₁and R₂ are each hydrogen or a substituted or unsubstituted C₁₋₂₀ linear,branched, or cyclic alkyl, alkoxy, or alkylthio group, or a single,multiple, or fused ring C₆ to C₂₄ aromatic group; x and y are each aninteger from 0 to 5; R₃ and R₄ are each selected from a single,multiple, or fused ring C₆ to C₂₄ aromatic group; and M includes an azogroup or a metal component. R₃ and R4 are each preferably selected froma C₆ to C₁₀ aromatic group, more preferably selected from phenyl,benzyl, naphthyl, benzamido, and benzothiazyl. R₁ and R₂ are eachpreferably selected from a substituted or unsubstituted C₁₋₁₀ linear,branched, or cyclic alkyl, alkoxy, or alkylthio group or a C₆ to C₁₀aromatic group. When R₁, R₂, R₃, or R₄, are substituted, thesubstitution may include one or more of the following substituentgroups: hydroxy and metal salts thereof; mercapto and metal saltsthereof; halogen; amino, nitro, cyano, and amido; carboxyl includingesters, acids, and metal salts thereof; silyl; acrylates and metal saltsthereof, sulfonyl or sulfonamide; and phosphates and phosphites. When Mis a metal component, it may be any suitable elemental metal availableto those of ordinary skill in the art. Typically, the metal will be atransition metal, although preferably it is tellurium or selenium.

Free Radical Source(s)

A free-radical source, often alternatively referred to as a free-radicalinitiator, is preferred in the composition and method. The free-radicalsource is typically a peroxide, and preferably an organic peroxide,which decomposes during the cure cycle. Suitable free-radical sourcesinclude organic peroxide compounds, such as di-t-amyl peroxide,di(2-t-butyl-peroxyisopropyl)benzene peroxide orα,α-bis(t-butylperoxy)diisopropylbenzene,1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane or1,1-di(t-butylperoxy)3,3,5-trimethylcyclohexane, dicumyl peroxide,di-t-butyl peroxide, 2,5-di-(t-butylperoxy)-2,5-dimethyl hexane,n-butyl-4,4-bis(t-butylperoxy)valerate, lauryl peroxide, benzoylperoxide, t-butyl hydroperoxide, and the like, and any mixture thereof.

Other examples include, but are not limited to, VAROX® 231XL and Varox®DCP-R, commercially available from Elf Atochem of Philadelphia, Pa.;PERKODOX® BC and PERKODOX® 14, commercially available from Akzo Nobel ofChicago, Ill.; and ELASTOCHEM® DCP-70, commercially available from RheinChemie of Trenton, N.J.

It is well known that peroxides are available in a variety of formshaving different activity. The activity is typically defined by the“active oxygen content.” For example, PERKODOX® BC peroxide is 98percent active and has an active oxygen content of 5.8 percent, whereasPERKODOX® DCP-70 is 70 percent active and has an active oxygen contentof 4.18 percent. The peroxide is may be present in an amount greaterthan about 0.1 parts per hundred of the total resilient polymercomponent, preferably about 0.1 to 15 parts per hundred of the resilientpolymer component, and more preferably about 0.2 to 5 parts per hundredof the total resilient polymer component. If the peroxide is present inpure form, it is preferably present in an amount of at least about 0.25phr, more preferably between about 0.35 phr and about 2.5 phr, and mostpreferably between about 0.5 phr and about 2 phr. Peroxides are alsoavailable in concentrate form, which are well-known to have differingactivities, as described above. In this case, if concentrate peroxidesare employed in the present invention, one skilled in the art would knowthat the concentrations suitable for pure peroxides are easily adjustedfor concentrate peroxides by dividing by the activity. For example, 2phr of a pure peroxide is equivalent 4 phr of a concentrate peroxidethat is 50 percent active (i.e., 2 divided by 0.5=4).

In one embodiment, the amount of free radical source is about 5 phr orless, but also may be about 3 phr or less. In another embodiment, theamount of free radical source is about 2.5 phr or less. In yet anotherembodiment, the amount of free radical source is about 2 phr or less. Instill another embodiment, the amount of free radical source is about 1phr or less preferably about 0.75 phr or less.

It should be understood by those of ordinary skill in the art that thepresence of certain cis-to-trans catalysts according to the invention bemore suited for a larger amount of free-radical source, such as theamounts described herein, compared to conventional cross-linkingreactions. The free radical source may alternatively or additionally beone or more of an electron beam, UV or gamma radiation, x-rays, or anyother high energy radiation source capable of generating free radicals.A skilled artisian is aware that heat often facilitates initiation ofthe generation of free radicals.

In one embodiment, the ratio of the free radical source to thecis-to-trans catalyst is about 10 or less, but also may be about 5 orless. Additionally, the ratio of the free radical source to thecis-to-trans catalyst may be from about 4 or less, but also may be about2 or less, and also may be about 1 or less. In another embodiment, theratio of the free radical source to the cis-to-trans catalyst is about0.5 or less, preferably about 0.4 or less. In yet another embodiment,the free radical source cis-to-trans catalyst ratio is greater thanabout 1.0. In still another embodiment, the free radical sourcecis-to-trans catalyst is about 1.5 or greater, preferably about 1.75 orgreater.

Crosslinking Agent(s)

Crosslinkers may be included to increase the hardness of the reactionproduct. Suitable crosslinking agents include one or more metallic saltsof unsaturated fatty acids having 3 to 8 carbon atoms, such as acrylicor methacrylic acid, or monocarboxylic acids, such as zinc, calcium, ormagnesium acrylate salts, and the like, and mixtures thereof. Examplesinclude, but are not limited to, one or more metal salt diacrylates,dimethacrylates, and monomethacrylates, wherein the metal is magnesium,calcium, zinc, aluminum, sodium, lithium, or nickel. Preferred acrylatesinclude zinc acrylate, zinc diacrylate, zinc methacrylate, zincdimethacrylate, and mixtures thereof. In one embodiment, zincmethacrylate is used in combination with the zinc salt ofpentachlorothiophenol.

The crosslinking agent must be present in an amount sufficient tocrosslink a portion of the chains of polymers in the resilient polymercomponent. For example, the desired compression may be obtained byadjusting the amount of crosslinking. This may be achieved, for example,by altering the type and amount of crosslinking agent, a methodwell-known to those of ordinary skill in the art. The crosslinking agentis typically present in an amount greater than about 0.1 percent of thepolymer component, preferably from about 10 to 50 percent of the polymercomponent, more preferably from about 10 to 40 percent of the polymercomponent.

In one embodiment, the crosslinking agent is present in an amountgreater than about 10 parts per hundred (“phr”) parts of the basepolymer, preferably from about 20 to about 40 phr of the base polymer,more preferably from about 25 to about 35 phr of the base polymer.

When an organosulfur is selected as the cis-to-trans catalyst, zincdiacrylate may be selected as the crosslinking agent and is present inan amount of less than about 25 phr.

Accelerator(s)

It is to be understood that when elemental sulfur or polymeric sulfur isincluded in the cis-to-trans catalyst, an accelerator may be used toimprove the performance of the cis-to-trans catalyst. Suitableaccelerators include, but are not limited to, sulfenamide, such asN-oxydiethylene 2-benzothiazole-sulfenamide, thiazole, such asbenzothiazyl disulfide, dithiocarbamate, such as bismuthdimethyldithiocarbamate, thiuram, such as tetrabenzyl thiuram disulfide,xanthate, such as zinc isopropyl xanthate, thiadiazine, thiourea, suchas trimethylthiourea, guanadine, such as N,N′-di-ortho-tolylguanadine,or aldehyde-amine, such as a butyraldehyde-aniline condensation product,or mixtures thereof.

Antioxidant

Typically, antioxidants are included in conventional golf ball corecompositions because antioxidants are included in the materials suppliedby manufacturers of compounds used in golf ball cores. Without beingbound to any particular theory, higher amounts of antioxidant in thereaction product may result in less trans-isomer content because theantioxidants consume at least a portion of the free radical source.Thus, even with high amounts of the free radical source in the reactionproduct described previously, such as for example about 3 phr, an amountof antioxidant greater than about 0.3 phr may significantly reduce theeffective amount of free radicals that are actually available to assistin a cis-to-trans conversion.

Because it is believed that the presence of antioxidants in thecomposition may inhibit the ability of free radicals to adequatelyassist in the cis-to-trans conversion, one way to ensure sufficientamounts of free radicals are provided for the conversion is to increasethe initial levels of free radicals present in the composition so thatsufficient amounts of free radicals remain after interaction withantioxidants in the composition. Thus, the initial amount of freeradicals provided in the composition may be increased by at least about10 percent, and more preferably are increased by at least about 25percent so that the effective amount of remaining free radicalssufficient to adequately provide the desired cis-to-trans conversion.Depending on the amount of antioxidant present in the composition, theinitial amount of free radicals may be increased by at least 50 percent,100 percent, or an even greater amount as needed. As discussed below,selection of the amount of free radicals in the composition may bedetermined based on a desired ratio of free radicals to antioxidant.Another approach is to reduce the levels of or eliminate antioxidants inthe composition. For instance, the reaction product of the presentinvention may be substantially free of antioxidants, thereby achievinggreater utilization of the free radicals toward the cis-to-transconversion. As used herein, the term “substantially free” generallymeans that the polybutadiene reaction product includes less than about0.3 phr of antioxidant, preferably less than about 0.1 phr ofantioxidant, more preferably less than about 0.05 phr of antioxidant,and most preferably about 0.01 phr or less antioxidant.

The amount of antioxidant has been shown herein to have a relationshipwith the amount of trans-isomer content after conversion. For example, apolybutadiene reaction product with 0.5 phr of antioxidant cured at 335°F. for 11 minutes results in about 15 percent trans-isomer content at anexterior surface of the center and about 13.4 percent at an interiorlocation after the conversion reaction. In contrast, the samepolybutadiene reaction product substantially free of antioxidantsresults in about 32 percent trans-isomer content at an exterior surfaceand about 21.4 percent at an interior location after the conversionreaction.

In one embodiment, the ratio of the free radical source to antioxidantis greater than about 10. In another embodiment, the ratio of the freeradical source to antioxidant is greater than about 25, preferablygreater than about 50. In yet another embodiment, the free radicalsource-antioxidant ratio is about 100 or greater. In still anotherembodiment, the free radical source-antioxidant ratio is about 200 orgreater, preferably 250 or greater, and more preferably about 300 orgreater.

If the reaction product is substantially free of antioxidants, theamount of the free radical source is preferably about 3 phr or less. Inone embodiment, the free radical source is present in an amount of about2.5 phr or less, preferably about 2 phr or less. In yet anotherembodiment, the amount of the free radical source in the reactionproduct is about 1.5 phr or less, preferably about 1 phr or less. Instill another embodiment, the free radical source is present is anamount of about 0.75 phr or less.

When the reaction product contains about 0.1 phr or greater antioxidant,the free radical source is preferably present in an amount of about 1phr or greater. In one embodiment, when the reaction product has about0.1 phr or greater antioxidant, the free radical source is present in anamount of about 2 phr or greater. In another embodiment, the freeradical source is present in an amount of about 2.5 phr or greater whenthe antioxidant is present in an amount of about 0.1 phr or greater.

In one embodiment, when the reaction product contains greater than about0.05 phr of antioxidant, the free radical source is preferably presentin an amount of about 0.5 phr or greater. In another embodiment, whenthe reaction product has greater than about 0.05 phr of antioxidant, thefree radical source is present in an amount of about 2 phr or greater.In yet another embodiment, the free radical source is present in anamount of about 2.5 phr or greater when the antioxidant is present in anamount of about 0.05 phr or greater.

Other Additives

Additional materials conventionally included in golf ball compositionsmay be added to the polybutadiene reaction product of the invention.These additional materials include, but are not limited to,density-adjusting fillers, coloring agents, reaction enhancers,crosslinking agents, whitening agents, UV absorbers, hindered aminelight stabilizers, defoaming agents, processing aids, and otherconventional additives. Stabilizers, softening agents, plasticizers,including internal and external plasticizers, impact modifiers, foamingagents, excipients, reinforcing materials and compatibilizers can alsobe added to any composition of the invention. All of these materials,which are well known in the art, are added for their usual purpose intypical amounts.

For example, the fillers discussed above with respect to thepolyurethane and polyurea compositions of the invention may be added tothe polybutadiene reaction product to affect Theological and mixingproperties, the specific gravity (i.e., density-modifying fillers), themodulus, the tear strength, reinforcement, and the like. Fillers mayalso be used to modify the weight of the core, e.g., a lower weight ballis preferred for a player having a low swing speed.

Trans-Isomer Conversion

As discussed above, it is preferable to increase cis-isomer totrans-isomer in polybutadiene core materials. In one embodiment, theamount of trans-isomer content after conversion is at least about 10percent or greater, while in another it is about 12 percent or greater.In another embodiment, the amount of trans-isomer content is about 15percent or greater after conversion. In yet another embodiment, theamount of trans-isomer content after conversion is about 20 percent orgreater, and more preferably is about 25 percent or greater. In stillanother embodiment, the amount of trans-isomer content after conversionis about 30 percent or greater, and preferably is about 32 percent orgreater. The amount of trans-isomer after conversion also may be about35 percent or greater, about 38 percent or greater, or even about 40percent or greater. In yet another embodiment, the amount oftrans-isomer after conversion may be about 42 percent or greater, oreven about 45 percent or greater.

The cured portion of the component including the reaction product of theinvention may have a first amount of trans-isomer polybutadiene at aninterior location and a second amount of trans-isomer polybutadiene atan exterior surface location. In one embodiment, the amount oftrans-isomer at the exterior surface location is greater than the amountof trans-isomer at an interior location. As will be further illustratedby the examples provided herein, the difference in trans-isomer contentbetween the exterior surface and the interior location after conversionmay differ depending on the cure cycle and the ratios of materials usedfor the conversion reaction. For example, it is also possible that thesedifferences can reflect a center with greater amounts of trans-isomer atthe interior portion than at the exterior portion.

The exterior portion of the center may have amounts of trans-isomerafter conversion in the amounts already indicated previously herein,such as in amounts about 10 percent or greater, about 12 percent orgreater, about 15 percent or greater, and the like, up to and includingamounts that are about 45 percent or greater as stated above. Forexample, in one embodiment of the invention, the polybutadiene reactionproduct may contain between about 35 percent to 60 percent of thetrans-isomer at the exterior surface of a center portion. Anotherembodiment has from about 40 percent to 50 percent of trans-isomer atthe exterior surface of a center portion. In one embodiment, thereaction product contains about 45 percent trans- isomer polybutadieneat the exterior surface of a center portion. In one embodiment, thereaction product at the center of the solid center portion may thencontain at least about 20 percent less trans-isomer than is present atthe exterior surface, preferably at least about 30 percent lesstrans-isomer, or at least about 40 percent less trans-isomer. In anotherembodiment, the amount of trans-isomer at the interior location is atleast about 6 percent less than is present at the exterior surface,preferably at least about 10 percent less than the second amount.

The gradient between the interior portion of the center and the exteriorportion of the center may vary. In one embodiment, the difference intrans-isomer content between the exterior and the interior afterconversion is about 3 percent or greater, while in another embodimentthe difference may be about 5 percent or greater. In another embodiment,the difference between the exterior surface and the interior locationafter conversion is about 10 percent or greater, and more preferably isabout 20 percent or greater. In yet another embodiment, the differencein trans-isomer content between the exterior surface and the interiorlocation after conversion may be about 5 percent or less, about 4percent or less, and even about 3 percent or less. In yet anotherembodiment, the difference between the exterior surface and the interiorlocation after conversion is less than about 1 percent.

Reaction Product Properties

The polybutadiene reaction product material preferably has a hardness ofat least about 15 Shore A, more preferably between about 30 Shore A and80 Shore D, and even more preferably between about 50 Shore A and 60Shore D. In addition, the specific gravity is typically greater thanabout 0.7, preferably greater than about 1, for the golf ballpolybutadiene material. Moreover, the polybutadiene reaction productpreferably has a flexural modulus of from about 500 psi to 300,000 psi,preferably from about 2,000 to 200,000 psi.

The desired loss tangent in the polybutadiene reaction product should beless than about 0.15 at −60° C. and less than about 0.05 at 30° C. whenmeasured at a frequency of 1 Hz and a 1 percent strain. In oneembodiment, the polybutadiene reaction product material preferably has aloss tangent below about 0.1 at −50° C., and more preferably below about0.07 at −50° C.

To produce golf balls having a desirable compressive stiffness, thedynamic stiffness of the polybutadiene reaction product material shouldbe less than about 50,000 N/m at −50° C. Preferably, the dynamicstiffness should be between about 10,000 and 40,000 N/m at −50° C., morepreferably, the dynamic stiffness should be between about 20,000 and30,000 N/m at −50° C.

In one embodiment, the reaction product has a first dynamic stiffnessmeasured at −50° C. that is less than about 130 percent of a seconddynamic stiffness measured at 0° C. In another embodiment, the firstdynamic stiffness is less than about 125 percent of the second dynamicstiffness. In yet another embodiment, the first dynamic stiffness isless than about 110 percent of the second dynamic stiffness.

Golf Ball Intermediate Layer(s)

When the golf ball of the present invention includes an intermediatelayer, such as an inner cover layer or outer core layer, i.e., anylayer(s) disposed between the inner core and the outer cover of a golfball, this layer can include any materials known to those of ordinaryskill in the art including thermoplastic and thermosetting materials.For example, the intermediate layer may be formed from any of thepolyurethane, polyurea, and polybutadiene materials discussed above.

The intermediate layer may also likewise include one or morehomopolymeric or copolymeric materials, such as:

-   -   (1) Vinyl resins, such as those formed by the polymerization of        vinyl chloride, or by the copolymerization of vinyl chloride        with vinyl acetate, acrylic esters or vinylidene chloride;    -   (2) Polyolefins, such as polyethylene, polypropylene,        polybutylene and copolymers such as ethylene methylacrylate,        ethylene ethylacrylate, ethylene vinyl acetate, ethylene        methacrylic or ethylene acrylic acid or propylene acrylic acid        and copolymers and homopolymers produced using a single-site        catalyst or a metallocene catalyst;    -   (3) Polyurethanes, such as those prepared from polyols and        diisocyanates or polyisocyanates and those disclosed in U.S.        Pat. No. 5,334,673;    -   (4) Polyureas, such as those disclosed in U.S. Pat. No.        5,484,870;    -   (5) Polyamides, such as poly(hexamethylene adipamide) and others        prepared from diamines and dibasic acids, as well as those from        amino acids such as poly(caprolactam), and blends of polyamides        with SURLYN, polyethylene, ethylene copolymers,        ethyl-propylene-non-conjugated diene terpolymer, and the like;    -   (6) Acrylic resins and blends of these resins with poly vinyl        chloride, elastomers, and the like;    -   (7) Thermoplastics, such as urethanes; olefinic thermoplastic        rubbers, such as blends of polyolefins with        ethylene-propylene-non-conjugated diene terpolymer; block        copolymers of styrene and butadiene, isoprene or        ethylene-butylene rubber; or copoly(ether-amide), such as PEBAX,        sold by ELF Atochem of Philadelphia, Pa.;    -   (8) Polyphenylene oxide resins or blends of polyphenylene oxide        with high impact polystyrene as sold under the trademark NORYL        by General Electric Company of Pittsfield, Mass.;    -   (9) Thermoplastic polyesters, such as polyethylene        terephthalate, polybutylene terephthalate, polyethylene        terephthalate/glycol modified and elastomers sold under the        trademarks HYTREL by E. I. DuPont de Nemours & Co. of        Wilmington, Del., and LOMOD by General Electric Company of        Pittsfield, Mass.;    -   (10) Blends and alloys, including polycarbonate with        acrylonitrile butadiene styrene, polybutylene terephthalate,        polyethylene terephthalate, styrene maleic anhydride,        polyethylene, elastomers, and the like, and polyvinyl chloride        with acrylonitrile butadiene styrene or ethylene vinyl acetate        or other elastomers; and    -   (11) Blends of thermoplastic rubbers with polyethylene,        propylene, polyacetal, nylon, polyesters, cellulose esters, and        the like.

In one embodiment, the intermediate layer includes polymers, such asethylene, propylene, butene-1 or hexane-1 based homopolymers orcopolymers including functional monomers, such as acrylic andmethacrylic acid and fully or partially neutralized ionomer resins andtheir blends, methyl acrylate, methyl methacrylate homopolymers andcopolymers, imidized, amino group containing polymers, polycarbonate,reinforced polyamides, polyphenylene oxide, high impact polystyrene,polyether ketone, polysulfone, poly(phenylene sulfide),acrylonitrile-butadiene, acrylic-styrene-acrylonitrile, poly(ethyleneterephthalate), poly(butylene terephthalate), poly(ethelyne vinylalcohol), poly(tetrafluoroethylene) and their copolymers includingfunctional comonomers, and blends thereof.

Ionomers

As briefly mentioned above, the intermediate layer may include ionomericmaterials, such as ionic copolymers of ethylene and an unsaturatedmonocarboxylic acid, which are available under the trademark SURLYN® ofE. I. DuPont de Nemours & Co., of Wilmington, Del., or IOTEK® or ESCOR®of Exxon. These are copolymers or terpolymers of ethylene andmethacrylic acid or acrylic acid totally or partially neutralized, i.e.,from about 1 to about 100 percent, with salts of zinc, sodium, lithium,magnesium, potassium, calcium, manganese, nickel or the like. In oneembodiment, the carboxylic acid groups are neutralized from about 10percent to about 100 percent. The carboxylic acid groups may alsoinclude methacrylic, crotonic, maleic, fumaric or itaconic acid. Thesalts are the reaction product of an olefin having from 2 to 10 carbonatoms and an unsaturated monocarboxylic acid having 3 to 8 carbon atoms.

The intermediate layer may also include at least one ionomer, such asacid-containing ethylene copolymer ionomers, including E/X/Y terpolymerswhere E is ethylene, X is an acrylate or methacrylate-based softeningcomonomer present in about 0 to 50 weight percent and Y is acrylic ormethacrylic acid present in about 5 to 35 weight percent. In anotherembodiment, the acrylic or methacrylic acid is present in about 8 to 35weight percent, more preferably 8 to 25 weight percent, and mostpreferably 8 to 20 weight percent.

The ionomer also may include so-called “low acid” and “high acid”ionomers, as well as blends thereof. In general, ionic copolymersincluding up to about 15 percent acid are considered “low acid”ionomers, while those including greater than about 15 percent acid areconsidered “high acid” ionomers.

A low acid ionomer is believed to impart high spin. Thus, in oneembodiment, the intermediate layer includes a low acid ionomer where theacid is present in about 10 to 15 weight percent and optionally includesa softening comonomer, e.g., iso- or n-butylacrylate, to produce asofter terpolymer. The softening comonomer may be selected from thegroup consisting of vinyl esters of aliphatic carboxylic acids whereinthe acids have 2 to 10 carbon atoms, vinyl ethers wherein the alkylgroups contains 1 to 10 carbon atoms, and alkyl acrylates ormethacrylates wherein the alkyl group contains 1 to 10 carbon atoms.Suitable softening comonomers include vinyl acetate, methyl acrylate,methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate,butyl methacrylate, or the like.

In another embodiment, the intermediate layer includes at least one highacid ionomer, for low spin rate and maximum distance. In this aspect,the acrylic or methacrylic acid is present in about 15 to about 35weight percent, making the ionomer a high modulus ionomer. In oneembodiment, the high modulus ionomer includes about 16 percent by weightof a carboxylic acid, preferably from about 17 percent to about 25percent by weight of a carboxylic acid, more preferably from about 18.5percent to about 21.5 percent by weight of a carboxylic acid. In somecircumstances, an additional comonomer such as an acrylate ester (i.e.,iso- or n-butylacrylate, etc.) can also be included to produce a softerterpolymer. The additional comonomer may be selected from the groupconsisting of vinyl esters of aliphatic carboxylic acids wherein theacids have 2 to 10 carbon atoms, vinyl ethers wherein the alkyl groupscontains 1 to 10 carbon atoms, and alkyl acrylates or methacrylateswherein the alkyl group contains 1 to 10 carbon atoms. Suitablesoftening comonomers include vinyl acetate, methyl acrylate, methylmethacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butylmethacrylate, or the like.

Consequently, examples of a number of copolymers suitable for use toproduce the high modulus ionomers include, but are not limited to, highacid embodiments of an ethylene/acrylic acid copolymer, anethylene/methacrylic acid copolymer, an ethylene/itaconic acidcopolymer, an ethylene/maleic acid copolymer, an ethylene/methacrylicacid/vinyl acetate copolymer, an ethylene/acrylic acid/vinyl alcoholcopolymer, and the like.

In one embodiment, the intermediate layer may be formed from at leastone polymer containing α,β-unsaturated carboxylic acid groups, or thesalts thereof, that have been 100 percent neutralized by organic fattyacids. The organic acids are aliphatic, mono-functional (saturated,unsaturated, or multi-unsaturated) organic acids. Salts of these organicacids may also be employed. The salts of organic acids of the presentinvention include the salts of barium, lithium, sodium, zinc, bismuth,chromium, cobalt, copper, potassium, strontium, titanium, tungsten,magnesium, cesium, iron, nickel, silver, aluminum, tin, or calcium,salts of fatty acids, particularly stearic, bebenic, erucic, oleic,linoelic or dimerized derivatives thereof. It is preferred that theorganic acids and salts of the present invention be relativelynon-migratory (they do not bloom to the surface of the polymer underambient temperatures) and non-volatile (they do not volatilize attemperatures required for melt-blending).

The acid moieties of the highly-neutralized polymers (“HNP”), typicallyethylene-based ionomers, are preferably neutralized greater than about70 percent, more preferably greater than about 90 percent, and mostpreferably at least about 100 percent. The HNP's may be also be blendedwith a second polymer component, which, if containing an acid group, maybe neutralized in a conventional manner, by organic fatty acids, orboth. The second polymer component, which may be partially or fullyneutralized, preferably comprises ionomeric copolymers and terpolymers,ionomer precursors, thermoplastics, polyamides, polycarbonates,polyesters, polyurethanes, polyureas, thermoplastic elastomers,polybutadiene rubber, balata, metallocene-catalyzed polymers (graftedand non-grafted), single-site polymers, high-crystalline acid polymers,cationic ionomers, and the like.

In this embodiment, the acid copolymers can be described as E/X/Ycopolymers where E is ethylene, X is an α,β-ethylenically unsaturatedcarboxylic acid, and Y is a softening comonomer. In a preferredembodiment, X is acrylic or methacrylic acid and Y is a C₁₋₈ alkylacrylate or methacrylate ester. X is preferably present in an amountfrom about 1 to about 35 weight percent of the polymer, more preferablyfrom about 5 to about 30 weight percent of the polymer, and mostpreferably from about 10 to about 20 weight percent of the polymer. Y ispreferably present in an amount from about 0 to about 50 weight percentof the polymer, more preferably from about 5 to about 25 weight percentof the polymer, and most preferably from about 10 to about 20 weightpercent of the polymer.

The organic acids are aliphatic, mono-functional (saturated,unsaturated, or multi-unsaturated) organic acids. Salts of these organicacids may also be employed. The salts of organic acids of the presentinvention include the salts of barium, lithium, sodium, zinc, bismuth,chromium, cobalt, copper, potassium, strontium, titanium, tungsten,magnesium, cesium, iron, nickel, silver, aluminum, tin, or calcium,salts of fatty acids, particularly stearic, bebenic, erucic, oleic,linoelic or dimerized derivatives thereof. It is preferred that theorganic acids and salts of the present invention be relativelynon-migratory (they do not bloom to the surface of the polymer underambient temperatures) and non-volatile (they do not volatilize attemperatures required for melt-blending).

Thermoplastic polymer components, such as copolyetheresters,copolyesteresters, copolyetheramides, elastomeric polyolefins, styrenediene block copolymers and their hydrogenated derivatives,copolyesteramides, thermoplastic polyurethanes, such ascopolyetherurethanes, copolyesterurethanes, copolyureaurethanes,epoxy-based polyurethanes, polycaprolactone-based polyurethanes,polyureas, and polycarbonate-based polyurethanes fillers, and otheringredients, if included, can be blended in either before, during, orafter the acid moieties are neutralized, thermoplastic polyurethanes.

Examples of these materials are disclosed in U.S. Patent ApplicationPublication Nos. 2001/0,018,375 and 2001/0,019,971, which areincorporated herein in their entirety by express reference thereto.

The ionomer compositions may also include at least one graftedmetallocene catalyzed polymers. Blends of this embodiment may includeabout 1 phr to about 100 phr of at least one grafted metallocenecatalyzed polymer and about 99 phr to 0 phr of at least one ionomer,preferably from about 5 phr to about 90 phr of at least one graftedmetallocene catalyzed polymer and about 95 phr to about 10 phr of atleast one ionomer, more preferably from about 10 phr to about 75 phr ofat least one grafted metallocene catalyzed polymer and about 90 phr toabout 25 phr of at least one ionomer, and most preferably from about 10phr to about 50 phr of at least one grafted metallocene catalyzedpolymer and about 90 phr to about 50 phr of at least one ionomer. Wherethe layer is foamed, the grafted metallocene catalyzed polymer blendsmay be foamed during molding by any conventional foaming or blowingagent.

In addition, polyamides, discussed in more detail below, may also beblended with ionomers.

Non-ionomeric Thermoplastic Materials

In another embodiment, the intermediate layer includes at least oneprimarily or fully non-ionomeric thermoplastic material. Suitablenon-ionomeric materials include polyamides and polyamide blends, graftedand non-grafted metallocene catalyzed polyolefins or polyamides,polyamide/ionomer blends, polyamide/nonionomer blends, polyphenyleneether/ionomer blends, and mixtures thereof. Examples of grafted andnon-grafted metallocene catalyzed polyolefins or polyamides,polyamide/ionomer blends, polyamide/nonionomer blends are disclosed inco-pending U.S. patent application Ser. No. 10/138,304, filed May 6,2002, entitled “Golf Ball Incorporating Grafted Metallocene CatalyzedPolymer Blends,” the entire disclosure of which is incorporated byreference herein.

In one embodiment, polyamide homopolymers, such as polyamide 6,18 andpolyamide 6,36 are used alone, or in combination with other polyamidehomopolymers. In another embodiment, polyamide copolymers, such aspolyamide 6,10/6,36, are used alone, or in combination with otherpolyamide copolymers. Other examples of suitable polyamide homopolymersand copolymers include polyamide polyamide 4, polyamide 6, polyamide 7,polyamide 11, polyamide 12 (manufactured as Rilsan AMNO by Elf Atochemof Philadelphia, Pa.), polyamide 13, polyamide 4,6, polyamide 6,6,polyamide 6,9, polyamide 6,10, polyamide 6,12, polyamide 6,36, polyamide12,12, polyamide 13,13, polyamide 6/6,6, polyamide 6,6/6,10, polyamide6/6,T wherein T represents terephthalic acid, polyamide 6/6,6/6,10,polyamide 6,10/6,36, polyamide 66,6,18, polyamide 66,6, 36, polyamide6/6,18, polyamide 6/6,36, polyamide 6/6,10/6,18, polyamide 6/6,10/6,36,polyamide 6,10/6,18, polyamide 6,12/6,18, polyamide 6,12/6,36, polyamide6/66/6,18, polyamide 6/66/6, 36, polyamide 66/6,10/6,18, polyamide66/6,10/6, 36, polyamide 6/6,12/6,18, polyamide 6/6,12/6,36, andmixtures thereof.

As mentioned above, any of the above polyamide homopolymer, copolymer,and homopolymer/copolymer blends may be optionally blended withnonionomer polymers, such as nonionomer thermoplastic polymers,nonionomer thermoplastic copolymers, nonionomer TPEs, and mixturesthereof.

One specific example of a polyamide-nonionomer blend is apolyamide-metallocene catalyzed polymer blend. The blended compositionsmay include grafted and/or non-grafted metallocene catalyzed polymers.Grafted metallocene catalyzed polymers, functionalized with pendantgroups, such as maleic anhydride, and the like, are available inexperimental quantities from DuPont. Grafted metallocene catalyzedpolymers may also be obtained by subjecting a commercially availablenon-grafted metallocene catalyzed polymer to a post-polymerizationreaction involving a monomer and an organic peroxide to provide agrafted metallocene catalyzed polymer with the desired pendant group orgroups.

Another example of a polyamide-nonionomer blend is a polyamide andnon-ionic polymers produced using non-metallocene single-site catalysts.As used herein, the term “non-metallocene catalyst” or non-metallocenesingle-site catalyst” refers to a single-site catalyst other than ametallocene catalyst. Examples of suitable single-site catalyzedpolymers are disclosed in co-pending U.S. patent application Ser. No.09/677,871, of which the entire disclosure is incorporated by referenceherein.

Nonionomers suitable for blending with the polyamide include, but arenot limited to, block copoly(ester)copolymers, blockcopoly(amide)copolymers, block copoly(urethane) copolymers,styrene-based block copolymers, thermoplastic and elastomer blendswherein the elastomer is not vulcanized (TEB), and thermoplastic andelastomer or rubber blends wherein the elastomer is dynamicallyvulcanized (TED). Other nonionomers suitable for blending with polyamideto form an intermediate layer composition include, but are not limitedto, polycarbonate, polyphenylene oxide, imidized, amino group containingpolymers, high impact polystyrene (HIPS), polyether ketone, polysulfone,poly(phenylene sulfide), reinforced engineering plastics,acrylic-styrene-acrylonitrile, poly(tetrafluoroethylene), poly(butylacrylate), poly(4-cyanobutyl acrylate), poly(2-ethylbutyl acrylate),poly(heptyl acrylate), poly(2-methylbutyl acrylate), poly(3-methylbutylacrylate), poly(N-octadecylacrylamide), poly(octadecyl methacrylate),poly(4-dodecylstyrene), poly(4-tetradecylstyrene), poly(ethylene oxide),poly(oxymethylene), poly(silazane), poly(furan tetracarboxylic aciddiimide), poly(acrylonitrile), poly(″-methylstyrene), as well as theclasses of polymers to which they belong and their copolymers, includingfunctional comonomers, and blends thereof.

In one embodiment, the non-ionomeric materials have a hardness of about60 Shore D or greater and a flexural modulus of about 30,000 psi orgreater.

Resilient Polymer-Reinforcing Polymer Blend

The intermediate layer may include a resilient polymer component, whichis preferably used as the majority of polymer in the intermediate layerto impart resilience in the cured state, and a reinforcing polymercomponent as a blend.

Resilient polymers suitable for use in the intermediate layer includepolybutadiene, polyisoprene, styrene-butadiene, styrene-propylene-dienerubber, ethylene-propylene-diene (EPDM), mixtures thereof, and the like,preferably having a high molecular weight of at least about 50,000 toabout 1,000,000. In one embodiment, the molecular weight is from about250,000 to about 750,000, and more preferably from about 200,000 toabout 400,000.

The reinforcing polymer component preferably has a glass transitiontemperature (T_(G)) sufficiently low to permit mixing without initiatingcrosslinking, preferably between about 35° C. to 120° C. In addition,the reinforcing polymer component preferably has a sufficiently lowviscosity at the mixing temperature when mixed with the resilientpolymer component to permit proper mixing of the two polymer components.The weight of the reinforcing polymer relative to the total compositionfor forming the intermediate layer generally ranges from about 5 to 25weight percent, preferably about 10 to 20 weight percent.

Examples of polymers suitable for use in the reinforcing polymercomponent include: trans-polyisoprene, block copolymer ether/ester,acrylic polyol, a polyethylene, a polyethylene copolymer,1,2-polybutadiene (syndiotactic), ethylene-vinyl acetate copolymer,trans-polycyclooctenenamer, trans-isomer polybutadiene, and mixturesthereof. Particularly suitable reinforcing polymers include: HYTREL3078, a block copolymer ether/ester commercially available from DuPontof Wilmington, Del.; a trans-isomer polybutadiene, such as FUREN 88obtained from Asahi Chemicals of Yako, Kawasakiku, Kawasakishi, Japan;KURRARAY TP251, a trans-polyisoprene commercially available fromKURRARAY CO.; LEVAPREN 700HV, an ethylene-vinyl acetate copolymercommercially available from Bayer-Rubber Division, Akron, Ohio; andVESTENAMER 8012, a trans-polycyclooctenenamer commercially availablefrom Huls America Inc. of Tallmadge, Ohio. Some suitable reinforcingpolymer components are listed in Table 1 below with their crystallinemelt temperature (T_(C)) and/or T_(G).

TABLE 1 REINFORCING POLYMER COMPONENTS T_(C) T_(G) Polymer TypeTradename (° C.) (° C.) Trans-polyisoprene KURRARAY TP251 60 −59Trans-polybutadiene FUREN 88 84 −88 Polyethylene Dow LPDE 98 −25Trans-polycyclo VESTENAMER 8012 54 octenenamer

Another polymer particularly suitable for use in the reinforcing polymercomponent is a rigidifying polybutadiene component, which typicallyincludes at least about 80 percent trans-isomer content with the restbeing cis-isomer 1,4-polybutadiene and vinyl-isomer 1,2-polybutadiene.Thus, it may be referred to herein as a “high trans-isomerpolybutadiene” or a “rigidifying polybutadiene” to distinguish it fromthe cis-isomer polybutadienes or polybutadienes having a lowtrans-isomer content, i.e., typically below 80 percent, used to form thegolf ball cores of the invention. The vinyl-content of the rigidifyingpolybutadiene component is preferably present in no more than about 15percent, preferably less than about 10 percent, more preferably lessthan about 5 percent, and most preferably less than about 3 percent ofthe polybutadiene isomers.

The rigidifying polybutadiene component, when used in a golf ball of theinvention, preferably has a polydispersity of no greater than about 4,preferably no greater than about 3, and more preferably no greater thanabout 2.5. The polydispersity, or PDI, is a ratio of the molecularweight average (M_(w)) over the molecular number average (M_(n)) of apolymer.

In addition, the rigidifying polybutadiene component, when used in agolf ball of the invention, typically has a high absolute molecularweight average, defined as being at least about 100,000, preferably fromabout 200,000 to 1,000,000. In one embodiment, the absolute molecularweight average is from about 230,000 to 750,000. In another embodiment,the molecular weight is about 275,000 to 700,000. In any embodimentwhere the vinyl-content is present in greater than about 10 percent, theabsolute molecular weight average is preferably greater than about200,000.

When trans-polyisoprene or high trans-isomer polybutadiene is includedin the reinforcing polymer component, it may be present in an amount ofabout 10 to 40 weight percent, preferably about 15 to 30 weight percent,more preferably about 15 to no more than 25 weight percent of thepolymer blend, i.e., the resilient and reinforcing polymer components.

The same crosslinking agents mentioned above with regard to the core maybe used in this embodiment to achieve the desired elastic modulus forthe resilient polymer—reinforcing polymer blend. In one embodiment, thecrosslinking agent is added in an amount from about 1 to about 50 partsper hundred of the polymer blend, preferably about 20 to about 45 partsper hundred, and more preferably about 30 to about 40 parts per hundred,of the polymer blend.

The resilient polymer component, reinforcing polymer component,free-radical initiator, and any other materials used in forming anintermediate layer of a golf ball core in accordance with invention maybe combined by any type of mixing known to one of ordinary skill in theart.

The intermediate layer may also be formed from the compositions asdisclosed in U.S. Pat. No. 5,688,191, the entire disclosure of which isincorporated by reference herein, which are listed in Table 2 below.

TABLE 2 INTERMEDIATE LAYER COMPOSITIONS AND PROPERTIES Flex TensileHardness Modulus Modulus % Strain at Sample (Shore D) Resilience (psi)(psi) Break 1A 0% Estane 58091 28 54 1,720 756 563 100% Estane 58861 1B25% Estane 58091 34 41 2,610 2,438 626 75% Estane 58861 1C 50% Estane58091 44 31 10,360 10,824 339 50% Estane 58861 1D 75% Estane 58091 61 3443,030 69,918 149 25% Estane 58861 1E 100% Estane 58091 78 46 147,240211,288 10 0% Estane 58861 2A 0% Hytrel 5556 40 47 8,500 7,071 527 100%Hytrel 4078 2B 25% Hytrel 5556 43 51 10,020 9,726 441 75% Hytrel 4078 2C50% Hytrel 5556 45 47 12,280 10,741 399 50% Hytrel 4078 2D 75% Hytrel5556 48 53 13,680 13,164 374 25% Hytrel 4078 2E 100% Hytrel 5556 48 5212,110 15,231 347 0% Hytrel 4078 3A 0% Hytrel 5556 30 62 3,240 2,078 810no break 100% Hytrel 3078 3B 25% Hytrel 5556 37 59 8,170 5,122 685 75%Hytrel 3078 3C 50% Hytrel 5556 44 55 15,320 10,879 590 50% Hytrel 30783D 75% Hytrel 5556 53 50 19,870 16,612 580 25% Hytrel 3078 3E 100%Hytrel 5556 58 50 54,840 17,531 575 0% Hytrel 3078 4A 0% Hytrel 4078 4651 11,150 8,061 597 100% Pebax 4033 4B 75% Hytrel 4078 46 53 10,3607,769 644 75% Pebax 4033 4C 50% Hytrel 4078 45 52 9,780 8,117 564 50%Pebax 4033 4D 75% Hytrel 4078 42 53 9,310 7,996 660 25% Pebax 4033 4E100% Hytrel 3078 40 51 9,250 6,383 531 0% Pebax 4033 5A 0% Hytrel 307877 50 156,070 182,869 9 100% Estane 58091 5B 25% Hytrel 3078 65 4887,680 96,543 33 75% Estane 58091 5C 50% Hytrel 3078 52 49 53,940 48,941102 50% Estane 58091 5D 75% Hytrel 3078 35 54 12,040 6,071 852 25%Estane 58091 5E 100% Hytrel 3078 29 50 3,240 2,078 810 no break 0%Estane 58091 6A 100% Kraton 1921 29 59 24,300 29,331 515 0% Estane 580910% Surlyn 7940 6B 50% Kraton 1921 57 49 56,580 — 145 50% Estane 58091 0%Surlyn 7940 6C 50% Kraton 1921 56 55 28,290 28,760 295 0% Estane 5809150% Surlyn 7940 7A 33.3% Pebax 4033 48 50 41,240 30,032 294 33.3% Estane58091 33.3% Hytrel 3078 7B 30% Pebax 4033 48 50 30,650 14,220 566 40%Estane 58091 10% Hytrel 3078 7C 20% Pebax 4033 41 54 24,020 16,630 51240% Estane 58091 40% Hytrel 3078Other Additives

Additional materials may be included in the intermediate layercompositions outlined above. For example, catalysts, coloring agents,optical brighteners, crosslinking agents, whitening agents such as TiO₂and ZnO, UV absorbers, hindered amine light stabilizers, defoamingagents, processing aids, surfactants, and other conventional additivesmay be added to the intermediate layer compositions of the invention. Inaddition, antioxidants, stabilizers, softening agents, plasticizers,including internal and external plasticizers, impact modifiers, foamingagents, density-adjusting fillers, reinforcing materials, andcompatibilizers may also be added to any of the intermediate layercompositions. One of ordinary skill in the art should be aware of therequisite amount for each type of additive to realize the benefits ofthat particular additive.

Golf Ball Cover(s)

The cover provides the interface between the ball and a club. Propertiesthat are desirable for the cover are good moldability, high abrasionresistance, high tear strength, high resilience, and good mold release,among others.

In one embodiment, at least one cover layer includes about 1 percent toabout 100 percent of the polyurethane composition of the invention. Inparticular, the cover may be formed from the reaction product of anisocyanate and a polyol, which is cured with a hydroxy-terminated oramine-terminated curing agent. In one embodiment, the cover layer isformed with a composition including a saturated isocyanate, a saturatedpolyol, and a modified curative blend, which includes a curing agent anda freezing point depressing agent.

In addition, polyurea compositions of the invention may be used to format least one cover layer of a golf ball of the present invention. Forexample, the cover layer may be formed with the reaction product of anisocyanate and a polyamine, which is cured with a modified curativeblend formed from a curing agent and a freezing point depressing agent.In one embodiment, the cover layer(s) may be formed from the reactionproduct of an saturated isocyanate and a saturated polyether amine,which is cured with a modifed curative blend preferably including anamine-terminated curing agent and an amine-terminated freezing pointdepressing agent.

The cover layer(s) may also be formed from composition blends asdiscussed above. For example, in one embodiment, at least one coverlayer is formed from a blend of about 10 percent to about 90 percentpolyurethane, preferably saturated, and about 90 percent to about 10percent other polymers and/or other materials. In another embodiment, atleast one cover layer is formed from a blend of about 10 percent toabout 90 percent polyurea, preferably saturated, and about 90 percent toabout 10 percent other polymers and/or other materials. In yet anotherembodiment, the cover compositions include from about 10 percent toabout 75 percent polyurethane or polyurea and about 90 percent to about25 percent other polymers and/or other materials, such as those listedabove.

Golf ball covers may also be formed of one or more homopolymeric orcopolymeric materials, such as:

-   -   (1) Vinyl resins, such as those formed by the polymerization of        vinyl chloride, or by the copolymerization of vinyl chloride        with vinyl acetate, acrylic esters or vinylidene chloride;    -   (2) Polyolefins, such as polyethylene, polypropylene,        polybutylene and copolymers such as ethylene methylacrylate,        ethylene ethylacrylate, ethylene vinyl acetate, ethylene        methacrylic or ethylene acrylic acid or propylene acrylic acid,        and copolymers and homopolymers produced using a single-site        catalyst;    -   (3) Polyurethanes, thermoplastic or thermoset, saturated or        unsaturated, aliphatic or aromatic, acid functionalized, such as        those prepared from polyols or amines and diisocyanates or        polyisocyanates and those disclosed in U.S. Pat. No. 5,334,673        and U.S. patent application Ser. No. 10/072,395;    -   (4) Polyureas, thermoplastic or thermoset, saturated or        unsaturated, aliphatic or aromatic, acid functionalized, such as        those disclosed in U.S. Pat. No. 5,484,870 and U.S. patent        application Ser. No. 10/072,395;    -   (5) Polyamides, such as poly(hexamethylene adipamide) and others        prepared from diamines and dibasic acids, as well as those from        amino acids such as poly(caprolactam), reinforced polyamides,        and blends of polyamides with ionomers, polyethylene, ethylene        copolymers, ethyl-propylene-non-conjugated diene terpolymer, and        the like;    -   (6) Acrylic resins and blends of these resins with poly vinyl        chloride, elastomers, and the like;    -   (7) Thermoplastics, such as urethanes; olefinic thermoplastic        rubbers, such as blends of polyolefins with        ethylene-propylene-non-conjugated diene terpolymer; block        copolymers of styrene and butadiene, isoprene or        ethylene-butylene rubber; or copoly(ether-amide), such as PEBAX,        sold by ELF Atochem of Philadelphia, Pa.;    -   (8) Polyphenylene oxide resins or blends of polyphenylene oxide        with high impact polystyrene as sold under the trademark NORYL        by General Electric Company of Pittsfield, Mass.;    -   (9) Thermoplastic polyesters, such as polyethylene        terephthalate, polybutylene terephthalate, polyethylene        terephthalate/glycol modified and elastomers sold under the        trademarks HYTREL by E. I. DuPont de Nemours & Co. of        Wilmington, Del., and LOMOD by General Electric Company of        Pittsfield, Mass.;    -   (10) Ethylene, propylene, 1-butene or 1-hexane based        homopolymers or copolymers including functional monomers, such        as acrylic and methacrylic acid or fully or partially        neutralized ionomer resins, and their blends, methyl acrylate,        methyl methacrylate homopolymers and copolymers, low acid        ionomers, high acid ionomers, and blends thereof;    -   (11) Blends and alloys, including polycarbonate with        acrylonitrile butadiene styrene, polybutylene terephthalate,        polyethylene terephthalate, styrene maleic anhydride,        polyethylene, elastomers, and the like, and polyvinyl chloride        with acrylonitrile butadiene styrene or ethylene vinyl acetate        or other elastomers; and    -   (12) Blends of thermoplastic rubbers with polyethylene,        propylene, polyacetal, nylon, polyesters, cellulose esters, and        the like.

The cover may also be at least partially formed from the polybutadienereaction product discussed above with respect to the core.

As discussed elsewhere herein, the composition may be molded onto thegolf ball in any known manner, such as by casting, compression molding,injection molding, reaction injection molding, or the like. One skilledin the art would appreciate that the molding method used may bedetermined at least partially by the properties of the composition. Forexample, casting may be preferred when the material is thermoset,whereas compression molding or injection molding may be preferred forthermoplastic compositions.

Golf Ball Construction

The compositions of the present invention may be used with any type ofball construction. For example, the ball may have a one-piece,two-piece, or three-piece design, a double core, a double cover, anintermediate layer(s), a multi-layer core, and/or a multi-layer coverdepending on the type of performance desired of the ball. As usedherein, the term “multilayer” means at least two layers. For example,the compositions of the invention may be used in a core, intermediatelayer, and/or cover of a golf ball, each of which may have a singlelayer or multiple layers.

As described above in the core section, a core may be a one-piece coreor a multilayer core, both of which may be solid, semi-solid, hollow,fluid-filled, or powder-filled. A multilayer core is one that has aninnermost component with an additional core layer or additional corelayers disposed thereon. For example, FIG. 1 shows a golf ball 1 havinga core 2 and a cover 3. In one embodiment, the golf ball of FIG. 1represents a core 2 of polybutadiene reaction material or otherconventional materials and a cover 3 including the polyurethanecomposition of the invention. In another embodiment, the golf ball ofFIG. 1 represents a core 2 formed from polybutadiene reaction materialand a cover 3 including the polyurea composition of the invention. Asdiscussed above, the both the polyurethane and polyurea compositions arepreferably saturated.

In addition, when the golf ball of the present invention includes anintermediate layer, such as an inner cover layer or outer core layer,i.e., any layer(s) disposed between the inner core and the outer coverof a golf ball, this layer may be incorporated, for example, with asingle layer or a multilayer cover, with a one-piece core or amultilayer core, with both a single layer cover and core, or with both amultilayer cover and a multilayer core. As with the core, theintermediate layer may also include a plurality of layers. It will beappreciated that any number or type of intermediate layers may be used,as desired.

FIG. 2 illustrates a multilayer golf ball 11, including a cover 13, atleast one intermediate layer 14, and a core 12. In one embodiment, thegolf ball 11 of FIG. 2 may include a core 12 of polybutadiene reactionmaterial, an intermediate layer 14, and a cover 13 formed of thepolyurethane composition of the invention, wherein the polyurethane ispreferably saturated. In another embodiment, the cover 13 in the golfball of FIG. 2 may be formed from a polyurea composition of theinvention. In addition, the golf ball 21 of FIG. 3 has a core 22 ofpolybutadiene reaction material or other conventional core materials, atleast one ionomer intermediate layer 24, and cover 23 including thesaturated polyurethane or saturated polyurea compositions of theinvention.

The intermediate layer may also be a tensioned elastomeric materialwound around a solid, semi-solid, hollow, fluid-filled, or powder-filledcenter. A wound layer may be described as a core layer or anintermediate layer for the purposes of the invention. As an example, thegolf ball 31 of FIG. 4 may include a core layer 32, a tensionedelastomeric layer 34 wound thereon, and a cover layer 33. In particular,the golf ball 31 of FIG. 4 may have a core 32 made of a polybutadienereaction product, an intermediate layer including a tensionedelastomeric material 34 and cover 33 including the polyurethane orpolyurea compositions of the invention. The tensioned elastomericmaterial may be formed of any suitable material known to those ofordinary skill in the art. In yet another embodiment, the wound, liquidcenter golf ball 41 of FIG. 5 has a hollow spherical core shell 42 withits hollow interior filled with a liquid 43, a thread rubber layerincluding a tensioned elastomeric material 44 and a cover 45 formed fromthe polyurethane or polyurea compositions of the invention.

In one embodiment, the tensioned elastomeric material incorporates thepolybutadiene reaction product discussed above. The tensionedelastomeric material may also be formed conventional polyisoprene. Inanother embodiment, the polyurea composition of the invention is used toform the tensioned elastomeric material. In another embodiment, solventspun polyether urea, as disclosed in U.S. Pat. No. 6,149,535, which isincorporated in its entirety by reference herein, is used to form thetensioned elastomeric material in an effort to achieve a smallercross-sectional area with multiple strands.

In one embodiment, the tensioned elastomeric layer is a high tensilefilament having a tensile modulus of about 10,000 kpsi or greater, asdisclosed in co-pending U.S. patent application Ser. No. 09/842,829,filed Apr. 27, 2001, entitled “All Rubber Golf Ball with Hoop-StressLayer,” the entire disclosure of which is incorporated by referenceherein. In another embodiment, the tensioned elastomeric layer is coatedwith a binding material that will adhere to the core and itself whenactivated, causing the strands of the tensioned elastomeric layer toswell and increase the cross-sectional area of the layer by at leastabout 5 percent. An example of such a golf ball construction is providedin co-pending U.S. patent application Ser. No. 09/841,910, the entiredisclosure of which is incorporated by reference herein.

The intermediate layer may also be formed of a binding material and aninterstitial material distributed in the binding material, wherein theeffective material properties of the intermediate layer are uniquelydifferent for applied forces normal to the surface of the ball fromapplied forces tangential to the surface of the ball. Examples of thistype of intermediate layer are disclosed in U.S. patent application Ser.No. 10/028,826, filed Dec. 28, 2001, entitled, “Golf Ball with aRadially Oriented Transversely Isotropic Layer and Manufacture of Same,”the entire disclosure of which is incorporated by reference herein. Inone embodiment of the present invention, the interstitial material mayextend from the intermediate layer into the core. In an alternativeembodiment, the interstitial material can also be embedded in the cover,or be in contact with the inner surface of the cover, or be embeddedonly in the cover.

At least one intermediate layer may also be a moisture barrier layer,such as the ones described in U.S. Pat. No. 5,820,488, which isincorporated by reference herein. Any suitable film-forming materialhaving a lower water vapor transmission rate than the other layersbetween the core and the outer surface of the ball, i.e., cover, primer,and clear coat. Examples include, but are not limited to polyvinylidenechloride, vermiculite, and a polybutadiene reaction product withfluorine gas. In one embodiment, the moisture barrier layer has a watervapor transmission rate that is sufficiently low to reduce the loss ofCOR of the golf ball by at least 5 percent if the ball is stored at 100°F. and 70 percent relative humidity for six weeks as compared to theloss in COR of a golf ball that does not include the moisture barrier,has the same type of core and cover, and is stored under substantiallyidentical conditions.

Prior to forming the cover layer, the inner ball, i.e., the core and anyintermediate layers disposed thereon, may be surface treated to increasethe adhesion between the outer surface of the inner ball and the cover.Examples of such surface treatment may include mechanically orchemically abrading the outer surface of the subassembly. Additionally,the inner ball may be subjected to corona discharge or plasma treatmentprior to forming the cover around it. Other layers of the ball, e.g.,the core, also may be surface treated. Examples of these and othersurface treatment techniques can be found in U.S. Pat. No. 6,315,915,which is incorporated by reference in its entirety.

Likewise, the cover may include a plurality of layers, e.g., an innercover layer disposed about a golf ball center and an outer cover layerformed thereon. For example, FIG. 6 may represent a golf ball 51 havinga core 52, a thin inner cover layer 54, and a thin outer cover layer 53disposed thereon. In particular, the core 51 may be formed of apolybutadiene reaction material, the inner cover layer 54 formed of anionomer blend, and the outer cover layer 53 formed of the polyurethaneor polyurea compositions of the invention. In addition, FIG. 7 mayrepresent a golf ball 61 having a core 62, an outer core layer 65, athin inner cover layer 64, and a thin outer cover layer 63 disposedthereon. In one embodiment, the core 62 and the outer core layer 65 areformed of the polybutadiene reaction material but differ in hardness,the inner cover layer 64 is formed of an ionomer blend, and the outercover layer 63 is formed of the polyurethane or polyurea compositions ofthe invention. Furthermore, the compositions of the invention may beused to form a golf ball 71, shown in FIG. 8, having a large core 72 anda thin outer cover layer 73. In one embodiment, the large core 72 isformed of a polybutadiene reaction material and the thin outer coverlayer 73 is formed of the polyurethane or polyurea compositions of theinvention, preferably acid functionalized, wherein the acid groups areat least partially neutralized.

While hardness gradients are typically used in a golf ball to achievecertain characteristics, the present invention also contemplates thecompositions of the invention being used in a golf ball with multiplecover layers having essentially the same hardness, wherein at least oneof the layers has been modified in some way to alter a property thataffects the performance of the ball. Such ball constructions aredisclosed in co-pending U.S. patent application Ser. No. 10/167,744,filed Jun. 13, 2002, entitled “Golf Ball with Multiple Cover Layers,”the entire disclosure of which is incorporated by reference herein.

In one such embodiment, both covers layers can be formed of the samematerial and have essentially the same hardness, but the layers aredesigned to have different coefficient of friction values. In anotherembodiment, the compositions of the invention are used in a golf ballwith multiple cover layers having essentially the same hardness, butdifferent rheological properties under high deformation. Another aspectof this embodiment relates to a golf ball with multiple cover layershaving essentially the same hardness, but different thicknesses tosimulate a soft outer cover over hard inner cover ball.

In another aspect of this concept, the cover layers of a golf ball haveessentially the same hardness, but different properties at high or lowtemperatures as compared to ambient temperatures. In particular, thisaspect of the invention is directed to a golf ball having multiple coverlayers wherein the outer cover layer composition has a lower flexuralmodulus at reduced temperatures than the inner cover layer, while thelayers retain the same hardness at ambient and reduced temperatures,which results in a simulated soft outer cover layer over a hard innercover layer feel. Certain polyureas may have a much more stable flexuralmodulus at different temperatures than ionomer resins and thus, could beused to make an effectively “softer” layer at lower temperatures than atambient or elevated temperatures.

Yet another aspect of this concept relates to a golf ball with multiplecover layers having essentially the same hardness, but differentproperties under wet conditions as compared to dry conditions.Wettability of a golf ball layer may be affected by surface roughness,chemical heterogeneity, molecular orientation, swelling, and interfacialtensions, among others. Thus, non-destructive surface treatments of agolf ball layer may aid in increasing the hydrophilicity of a layer,while highly polishing or smoothing the surface of a golf ball layer maydecrease wettability. U.S. Pat. Nos. 5,403,453 and 5,456,972 disclosemethods of surface treating polymer materials to affect the wettability,the entire disclosures of which are incorporated by reference herein. Inaddition, plasma etching, corona treating, and flame treating may beuseful surface treatments to alter the wettability to desiredconditions. Wetting agents may also be added to the golf ball layercomposition to modify the surface tension of the layer.

Thus, the differences in wettability of the cover layers according tothe invention may be measured by a difference in contact angle. Thecontact angles for a layer may be from about 1° (low wettability) toabout 180° (very high wettability). In one embodiment, the cover layershave contact angles that vary by about 1° or greater. In anotherembodiment, the contact angles of the cover layer vary by about 3° orgreater. In yet another embodiment, the contact angles of the coverlayers vary by about 5° or greater.

Other non-limiting examples of suitable types of ball constructions thatmay be used with the present invention include those described in U.S.Pat. Nos. 6,056,842, 5,688,191, 5,713,801, 5,803,831, 5,885,172,5,919,100, 5,965,669, 5,981,654, 5,981,658, and 6,149,535, as well as inPublication Nos. US2001/0,009,310 A1, US2002/0,025,862, andUS2002/0,028,885. The entire disclosures of these patents and publishedpatent applications are incorporated by reference herein.

Methods of Forming Layers

The golf balls of the invention may be formed using a variety ofapplication techniques such as compression molding, flip molding,injection molding, retractable pin injection molding, reaction injectionmolding (RIM), liquid injection molding (LIM), casting, vacuum forming,powder coating, flow coating, spin coating, dipping, spraying, and thelike. A method of injection molding using a split vent pin can be foundin co-pending U.S. patent application Ser. No. 09/742,435, filed Dec.22, 2000, entitled “Split Vent Pin for Injection Molding.” Examples ofretractable pin injection molding may be found in U.S. Pat. Nos.6,129,881, 6,235,230, and 6,379,138. These molding references areincorporated in their entirety by reference herein. In addition, achilled chamber, i.e., a cooling jacket, such as the one disclosed inU.S. patent application Ser. No. 09/717,136, filed Nov. 22, 2000,entitled “Method of Making Golf Balls” may be used to cool thecompositions of the invention when casting, which also allows for ahigher loading of catalyst into the system.

Conventionally, compression molding and injection molding are applied tothermoplastic materials, whereas RIM, liquid injection molding, andcasting are employed on thermoset materials. These and other manufacturemethods are disclosed in U.S. Pat. Nos. 6,207,784, 5,484,870, and, thedisclosures of which are incorporated herein by reference in theirentirety.

Forming the Core Layer(s)

The cores of the invention may be formed by any suitable method known tothose of ordinary skill in art. When the cores are formed from athermoset material, compression molded is a particularly suitable methodof forming the core. In a thermoplastic core embodiment, on the otherhand, the cores may be injection molded.

For example, methods of converting the cis-isomer of the polybutadieneresilient polymer core component to the trans-isomer during a moldingcycle are known to those of ordinary skill in the art. Suitable methodsinclude single pass mixing (ingredients are added sequentially),multi-pass mixing, and the like. The crosslinking agent, and any otheroptional additives used to modify the characteristics of the golf ballcenter or additional layer(s), may similarly be combined by any type ofmixing. Suitable mixing equipment is well known to those of ordinaryskill in the art, and such equipment may include a Banbury mixer, atwo-roll mill, or a twin screw extruder. Suitable mixing speeds andtemperatures are well-known to those of ordinary skill in the art, ormay be readily determined without undue experimentation.

The mixture can be subjected to, e.g., a compression or injectionmolding process, and the molding cycle may have a single step of moldingthe mixture at a single temperature for a fixed-time duration. In oneembodiment, a single-step cure cycle is employed. Although the curingtime depends on the various materials selected, a suitable curing timeis about 5 to about 18 minutes, preferably from about 8 to about 15minutes, and more preferably from about 10 to about 12 minutes. Anexample of a single step molding cycle, for a mixture that containsdicumyl peroxide, would hold the polymer mixture at 171° C. (340° F.)for a duration of 15 minutes. An example of a two-step molding cyclewould be holding the mold at 143° C. (290° F.) for 40 minutes, thenramping the mold to 171° C. (340° F.) where it is held for a duration of20 minutes. Those of ordinary skill in the art will be readily able toadjust the curing time based on the particular materials used and thediscussion herein.

Furthermore, U.S. Pat. Nos. 6,180,040 and 6,180,722 disclose methods ofpreparing dual core golf balls. The disclosures of these patents arehereby incorporated by reference in their entirety.

Forming the Intermediate Layer(s)

The intermediate layer may also be formed from using any suitable methodknown to those of ordinary skill in the art. For example, anintermediate layer may be formed by blow molding and covered with adimpled cover layer formed by injection molding, compression molding,casting, vacuum forming, powder coating, and the like.

Forming the Cover Layer(s)

The polyurethane and polyurea compositions of the invention may beapplied over an inner ball using a variety of application techniquessuch as spraying, compression molding, dipping, spin coating, or flowcoating methods that are well known in the art. In one embodiment, thepolyurethane or polyurea composition is used to form a cover over thecore using a combination of casting and compression molding.Conventionally, compression molding and injection molding are applied tothermoplastic cover materials, whereas RIM, liquid injection molding,and casting are employed on thermoset cover materials.

U.S. Pat. No. 5,733,428, the entire disclosure of which is herebyincorporated by reference, discloses a useful method for forming apolyurethane cover on a golf ball core. Because this method relates tothe use of both casting thermosetting and thermoplastic material as thegolf ball cover, wherein the cover is formed around the core by mixingand introducing the material in mold halves, the polyurea compositionsof the invention may also be used employing the same casting process.

For example, once either of the polyurethane or polyurea composition ismixed, an exothermic reaction commences and continues until the materialis solidified around the core. It is important that the viscosity bemeasured over time, so that the subsequent steps of filling each moldhalf, introducing the core into one half and closing the mold can beproperly timed for accomplishing centering of the core cover halvesfusion and achieving overall uniformity. A suitable viscosity range ofthe curing mix for introducing cores into the mold halves is determinedto be approximately between about 2,000 cP and about 30,000 cP, with thepreferred range of about 8,000 cP to about 15,000 cP.

To start the cover formation, mixing of the prepolymer and curative isaccomplished in a motorized mixer inside a mixing head by feedingthrough lines metered amounts of curative and prepolymer. Top preheatedmold halves are filled and placed in fixture units using centering pinsmoving into apertures in each mold. At a later time, the cavity of abottom mold half, or the cavities of a series of bottom mold halves, isfilled with similar mixture amounts as used for the top mold halves.After the reacting materials have resided in top mold halves for about40 to about 100 seconds, preferably for about 70 to about 80 seconds, acore is lowered at a controlled speed into the gelling reacting mixture.

A ball cup holds the ball core through reduced pressure (or partialvacuum). Upon location of the core in the halves of the mold aftergelling for about 4 to about 12 seconds, the vacuum is released allowingthe core to be released. In one embodiment, the vacuum is releasedallowing the core to be released after about 5 seconds to 10 seconds.The mold halves, with core and solidified cover half thereon, areremoved from the centering fixture unit, inverted and mated with secondmold halves which, at an appropriate time earlier, have had a selectedquantity of reacting prepolymer and curing agent introduced therein tocommence gelling.

Similarly, U.S. Pat. No. 5,006,297 and U.S. Pat. No. 5,334,673 both alsodisclose suitable molding techniques that may be utilized to apply thecastable reactive liquids employed in the present invention. However,the method of the invention is not limited to the use of thesetechniques; other methods known to those skilled in the art may also beemployed. For instance, other methods for holding the ball core may beutilized instead of using a partial vacuum.

Dimples

The use of various dimple patterns and profiles provides a relativelyeffective way to modify the aerodynamic characteristics of a golf ball.As such, the manner in which the dimples are arranged on the surface ofthe ball can be by any available method. For instance, the ball may havean icosahedron-based pattern, such as described in U.S. Pat. No.4,560,168, or an octahedral-based dimple patterns as described in U.S.Pat. No. 4,960,281.

In one embodiment of the present invention, the golf ball has anicosahedron dimple pattern that includes 20 triangles made from about362 dimples and, except perhaps for the mold parting line, does not havea great circle that does not intersect any dimples. Each of the largetriangles, preferably, has an odd number of dimples (7) along each sideand the small triangles have an even number of dimples (4) along eachside. To properly pack the dimples, the large triangle has nine moredimples than the small triangle. In another embodiment, the ball hasfive different sizes of dimples in total. The sides of the largetriangle have four different sizes of dimples and the small triangleshave two different sizes of dimples.

In another embodiment of the present invention, the golf ball has anicosahedron dimple pattern with a large triangle including threedifferent dimples and the small triangles having only one diameter ofdimple. In a preferred embodiment, there are 392 dimples and one greatcircle that does not intersect any dimples. In another embodiment, morethan five alternative dimple diameters are used.

In one embodiment of the present invention, the golf ball has anoctahedron dimple pattern including eight triangles made from about 440dimples and three great circles that do not intersect any dimples. Inthe octahedron pattern, the pattern includes a third set of dimplesformed in a smallest triangle inside of and adjacent to the smalltriangle. To properly pack the dimples, the large triangle has nine moredimples than the small triangle and the small triangle has nine moredimples than the smallest triangle. In this embodiment, the ball has sixdifferent dimple diameters distributed over the surface of the ball. Thelarge triangle has five different dimple diameters, the small trianglehas three different dimple diameters and the smallest triangle has twodifferent dimple diameters.

Alternatively, the dimple pattern can be arranged according tophyllotactic patterns, such as described in U.S. Pat. No. 6,338,684,which is incorporated herein in its entirety.

Dimple patterns may also be based on Archimedean patterns including atruncated octahedron, a great rhombcuboctahedron, a truncateddodecahedron, and a great rhombicosidodecahedron, wherein the patternhas a non-linear parting line, as disclosed in U.S. patent applicationSer. No. 10/078,417, which is incorporated by reference herein.

The golf balls of the present invention may also be covered withnon-circular shaped dimples, i.e., amorphous shaped dimples, asdisclosed in U.S. Pat. No. 6,409,615, which is incorporated in itsentirety by reference herein.

Dimple patterns that provide a high percentage of surface coverage arepreferred, and are well known in the art. For example, U.S. Pat. Nos.5,562,552, 5,575,477, 5,957,787, 5,249,804, and 4,925,193 disclosegeometric patterns for positioning dimples on a golf ball. In oneembodiment, the golf balls of the invention have a dimple coverage ofthe surface area of the cover of at least about 60 percent, preferablyat least about 65 percent, and more preferably at least 70 percent orgreater. Dimple patterns having even higher dimple coverage values mayalso be used with the present invention. Thus, the golf balls of thepresent invention may have a dimple coverage of at least about 75percent or greater, about 80 percent or greater, or even about 85percent or greater.

In addition, a tubular lattice pattern, such as the one disclosed inU.S. Pat. No. 6,290,615, which is incorporated by reference in itsentirety herein, may also be used with golf balls of the presentinvention. The golf balls of the present invention may also have aplurality of pyramidal projections disposed on the intermediate layer ofthe ball, as disclosed in U.S. Pat. No. 6,383,092, which is incorporatedin its entirety by reference herein. The plurality of pyramidalprojections on the golf ball may cover between about 20 percent to about80 of the surface of the intermediate layer.

In an alternative embodiment, the golf ball may have a non-planarparting line allowing for some of the plurality of pyramidal projectionsto be disposed about the equator. Such a golf ball may be fabricatedusing a mold as disclosed in co-pending U.S. patent application Ser. No.09/442,845, filed Nov. 18, 1999, entitled “Mold For A Golf Ball,” andwhich is incorporated in its entirety by reference herein. Thisembodiment allows for greater uniformity of the pyramidal projections.

Several additional non-limiting examples of dimple patterns with varyingsizes of dimples are also provided in U.S. patent application Ser. No.09/404,164, filed Sep. 27, 1999, entitled “Golf Ball Dimple Patterns,”and U.S. Pat. No. 6,213,898, the entire disclosures of which areincorporated by reference herein.

The total number of dimples on the ball, or dimple count, may varydepending such factors as the sizes of the dimples and the patternselected. In general, the total number of dimples on the ball preferablyis between about 100 to about 1000 dimples, although one skilled in theart would recognize that differing dimple counts within this range cansignificantly alter the flight performance of the ball. In oneembodiment, the dimple count is about 380 dimples or greater, but morepreferably is about 400 dimples or greater, and even more preferably isabout 420 dimples or greater. In one embodiment, the dimple count on theball is about 422 dimples. In some cases, it may be desirable to havefewer dimples on the ball. Thus, one embodiment of the present inventionhas a dimple count of about 380 dimples or less, and more preferably isabout 350 dimples or less.

Dimple profiles revolving a catenary curve about its symmetrical axismay increase aerodynamic efficiency, provide a convenient way to alterthe dimples to adjust ball performance without changing the dimplepattern, and result in uniformly increased flight distance for golfersof all swing speeds. Thus, catenary curve dimple profiles, as disclosedin U.S. patent application Ser. No. 09/989,191, filed Nov. 21, 2001,entitled “Golf Ball Dimples with a Catenary Curve Profile,” which isincorporated in its entirety by reference herein, is contemplated foruse with the golf balls of the present invention.

Golf Ball Post-Processing

The golf balls of the present invention may be painted, coated, orsurface treated for further benefits.

For example, golf balls covers frequently contain a fluorescent materialand/or a dye or pigment to achieve the desired color characteristics. Agolf ball of the invention may also be treated with a base resin paintcomposition, however, as disclosed in U.S. Patent Publication No.2002/0,082,358, which includes a 7-triazinylamino-3-phenylcoumarinderivative as the fluorescent whitening agent to provide improvedweather resistance and brightness.

In addition, trademarks or other indicia may be stamped, i.e.,pad-printed, on the outer surface of the ball cover, and the stampedouter surface is then treated with at least one clear coat to give theball a glossy finish and protect the indicia stamped on the cover.

The golf balls of the invention may also be subjected to dyesublimation, wherein at least one golf ball component is subjected to atleast one sublimating ink that migrates at a depth into the outersurface and forms an indicia. The at least one sublimating inkpreferably includes at least one of an azo dye, a nitroarylamine dye, oran anthraquinone dye. U.S. patent application Ser. No. 10/012,538, filedDec. 12, 2001, entitled, “Method of Forming Indicia on a Golf Ball,” theentire disclosure of which is incorporated by reference herein.

Laser marking of a selected surface portion of a golf ball causing thelaser light-irradiated portion to change color is also contemplated foruse with the present invention. U.S. Pat. Nos. 5,248,878 and 6,075,223generally disclose such methods, the entire disclosures of which areincorporated by reference herein. In addition, the golf balls may besubjected to ablation, i.e., directing a beam of laser radiation onto aportion of the cover, irradiating the cover portion, wherein theirradiated cover portion is ablated to form a detectable mark, whereinno significant discoloration of the cover portion results therefrom.Ablation is discussed in U.S. patent application Ser. No. 09/739,469,filed Dec. 18, 2002, entitled “Laser Marking of Golf Balls,” which isincorporated in its entirety by reference herein.

Protective and decorative coating materials, as well as methods ofapplying such materials to the surface of a golf ball cover are wellknown in the golf ball art. Generally, such coating materials compriseurethanes, urethane hybrids, epoxies, polyesters and acrylics. Ifdesired, more than one coating layer can be used. The coating layer(s)may be applied by any suitable method known to those of ordinary skillin the art. In one embodiment, the coating layer(s) is applied to thegolf ball cover by an in-mold coating process, such as described in U.S.Pat. No. 5,849,168, which is incorporated in its entirety by referenceherein.

The use of the saturated polyurea and polyurethane compositions in golfequipment obviates the need for typical post-processing, e.g., coating agolf ball with a pigmented coating prior to applying a clear topcoat tothe ball. Unlike compositions with no light stable properties, thecompositions used in forming the golf equipment of the present inventiondo not discolor upon exposure, especially related or extended exposure,to light. Also, by eliminating at least one coating step, themanufacturer realizes economic benefits in terms of reduced processtimes and consequent improved labor efficiency. Further, significantreduction in volatile organic compounds (“VOCs”), typical constituentsof paint, may be realized through the use of the present invention,offering significant environmental benefits.

Thus, while it is not necessary to use pigmented coating on the golfballs of the present invention when formed with the saturatedcompositions, the golf balls of the present invention may be painted,coated, or surface treated for further benefits. For example, the valueof golf balls made according to the invention and painted offer enhancedcolor stability as degradation of the surface paint occurs during thenormal course of play. The mainstream technique used nowadays forhighlighting whiteness is to form a cover toned white with titaniumdioxide, subjecting the cover to such surface treatment as coronatreatment, plasma treatment, UV treatment, flame treatment, or electronbeam treatment, and applying one or more layers of clear paint, whichmay contain a fluorescent whitening agent. This technique is productiveand cost effective.

Golf Ball Properties

The properties such as hardness, modulus, core diameter, intermediatelayer thickness and cover layer thickness of the golf balls of thepresent invention have been found to effect play characteristics such asspin, initial velocity and feel of the present golf balls. For example,the flexural and/or tensile modulus of the intermediate layer arebelieved to have an effect on the “feel” of the golf balls of thepresent invention.

Component Dimensions

Dimensions of golf ball components, i.e., thickness and diameter, mayvary depending on the desired properties. For the purposes of theinvention, any layer thickness may be employed. Non-limiting examples ofthe various embodiments outlined above are provided here with respect tolayer dimensions.

The present invention relates to golf balls of any size. While USGAspecifications limit the size of a competition golf ball to more than1.68 inches in diameter, golf balls of any size can be used for leisuregolf play. The preferred diameter of the golf balls is from about 1.68inches to about 1.8 inches. The more preferred diameter is from about1.68 inches to about 1.76 inches. A diameter of from about 1.68 inchesto about 1.74 inches is most preferred, however diameters anywhere inthe range of from 1.7 to about 1.95 inches can be used. Preferably, theoverall diameter of the core and all intermediate layers is about 80percent to about 98 percent of the overall diameter of the finishedball.

The core may have a diameter ranging from about 0.09 inches to about1.65 inches. In one embodiment, the diameter of the core of the presentinvention is about 1.2 inches to about 1.630 inches. In anotherembodiment, the diameter of the core is about 1.3 inches to about 1.6inches, preferably from about 1.39 inches to about 1.6 inches, and morepreferably from about 1.5 inches to about 1.6 inches. In yet anotherembodiment, the core has a diameter of about 1.55 inches to about 1.65inches.

The core of the golf ball may also be extremely large in relation to therest of the ball. For example, in one embodiment, the core makes upabout 90 percent to about 98 percent of the ball, preferably about 94percent to about 96 percent of the ball. In this embodiment, thediameter of the core is preferably about 1.54 inches or greater,preferably about 1.55 inches or greater. In one embodiment, the corediameter is about 1.59 inches or greater. In another embodiment, thediameter of the core is about 1.64 inches or less.

When the core includes an inner core layer and an outer core layer, theinner core layer is preferably about 0.9 inches or greater and the outercore layer preferably has a thickness of about 0.1 inches or greater. Inone embodiment, the inner core layer has a diameter from about 0.09inches to about 1.2 inches and the outer core layer has a thickness fromabout 0.1 inches to about 0.8 inches. In yet another embodiment, theinner core layer diameter is from about 0.095 inches to about 1.1 inchesand the outer core layer has a thickness of about 0.20 inches to about0.03 inches.

The cover typically has a thickness to provide sufficient strength, goodperformance characteristics, and durability. In one embodiment, thecover thickness is from about 0.02 inches to about 0.35 inches. Thecover preferably has a thickness of about 0.02 inches to about 0.12inches, preferably about 0.1 inches or less. When the compositions ofthe invention are used to form the outer cover of a golf ball, the covermay have a thickness of about 0.1 inches or less, preferably about 0.07inches or less. In one embodiment, the outer cover has a thickness fromabout 0.02 inches to about 0.07 inches. In another embodiment, the coverthickness is about 0.05 inches or less, preferably from about 0.02inches to about 0.05 inches. In yet another embodiment, the outer coverlayer of such a golf ball is between about 0.02 inches and about 0.045inches. In still another embodiment, the outer cover layer is about0.025 to about 0.04 inches thick. In one embodiment, the outer coverlayer is about 0.03 inches thick.

The range of thicknesses for an intermediate layer of a golf ball islarge because of the vast possibilities when using an intermediatelayer, i.e., as an outer core layer, an inner cover layer, a woundlayer, a moisture/vapor barrier layer. When used in a golf ball of theinvention, the intermediate layer, or inner cover layer, may have athickness about 0.3 inches or less. In one embodiment, the thickness ofthe intermediate layer is from about 0.002 inches to about 0.1 inches,preferably about 0.01 inches or greater. In one embodiment, thethickness of the intermediate layer is about 0.09 inches or less,preferably about 0.06 inches or less. In another embodiment, theintermediate layer thickness is about 0.05 inches or less, morepreferably about 0.01 inches to about 0.045 inches. In one embodiment,the intermediate layer, thickness is about 0.02 inches to about 0.04inches. In another embodiment, the intermediate layer thickness is fromabout 0.025 inches to about 0.035 inches. In yet another embodiment, thethickness of the intermediate layer is about 0.035 inches thick. Instill another embodiment, the inner cover layer is from about 0.03inches to about 0.035 inches thick. Varying combinations of these rangesof thickness for the intermediate and outer cover layers may be used incombination with other embodiments described herein.

The ratio of the thickness of the intermediate layer to the outer coverlayer is preferably about 10 or less, preferably from about 3 or less.In another embodiment, the ratio of the thickness of the intermediatelayer to the outer cover layer is about 1 or less. The core andintermediate layer(s) together form an inner ball preferably having adiameter of about 1.48 inches or greater for a 1.68-inch ball. In oneembodiment, the inner ball of a 1.68-inch ball has a diameter of about1.52 inches or greater. In another embodiment, the inner ball of a1.68-inch ball has a diameter of about 1.66 inches or less. In yetanother embodiment, a 1.72-inch (or more) ball has an inner balldiameter of about 1.50 inches or greater. In still another embodiment,the diameter of the inner ball for a 1.72-inch ball is about 1.70 inchesor less.

Hardness

Most golf balls consist of layers having different hardnesses, e.g.,hardness gradients, to achieve desired performance characteristics. Thepresent invention contemplates golf balls having hardness gradientsbetween layers, as well as those golf balls with layers having the samehardness.

It should be understood, especially to one of ordinary skill in the art,that there is a fundamental difference between “material hardness” and“hardness, as measured directly on a golf ball.” Material hardness isdefined by the procedure set forth in ASTM-D2240 and generally involvesmeasuring the hardness of a flat “slab” or “button” formed of thematerial of which the hardness is to be measured. Hardness, whenmeasured directly on a golf ball (or other spherical surface) is acompletely different measurement and, therefore, results in a differenthardness value. This difference results from a number of factorsincluding, but not limited to, ball construction (i.e., core type,number of core and/or cover layers, etc.), ball (or sphere) diameter,and the material composition of adjacent layers. It should also beunderstood that the two measurement techniques are not linearly relatedand, therefore, one hardness value cannot easily be correlated to theother.

The cores of the present invention may have varying hardnesses dependingon the particular golf ball construction. In one embodiment, the corehardness is at least about 15 Shore A, preferably about 30 Shore A, asmeasured on a formed sphere. In another embodiment, the core has ahardness of about 50 Shore A to about 90 Shore D. In yet anotherembodiment, the hardness of the core is about 80 Shore D or less.Preferably, the core has a hardness about 30 to about 65 Shore D, andmore preferably, the core has a hardness about 35 to about 60 Shore D.

When a polybutadiene reaction product is incorporated into a core, thecore may have a hardness gradient, i.e., a first hardness at a firstpoint, i.e., at an interior location, and a second hardness at a secondpoint, i.e., at an exterior surface, as measured on a molded sphere. Inone embodiment, the second hardness is at least about 6 percent greaterthan the first hardness, preferably about 10 percent greater than thefirst hardness. In other embodiments, the second hardness is at leastabout 20 percent greater or at least about 30 percent greater, than thefirst hardness.

For example, the interior of the core may have a first hardness of about45 Shore C to about 60 Shore C and the exterior surface of the core mayhave a second hardness of about 65 Shore C to about 75 Shore C. In onegolf ball formulated according to the invention, the first hardness wasabout 51 Shore C and a second hardness was about 71 Shore C, providing ahardness difference of greater than 20 percent.

In one embodiment, however, the core has a substantially uniformhardness throughout. Thus, in this aspect, the first and second hardnesspreferably differ by about 5 percent or less, more preferably about 3percent or less, and even more preferably by about 2 percent or less. Inanother embodiment, the hardness is uniform throughout the component.

The intermediate layer(s) of the present invention may also vary inhardness depending on the specific construction of the ball. In oneembodiment, the hardness of the intermediate layer is about 30 Shore Dor greater. In another embodiment, the hardness of the intermediatelayer is about 90 Shore D or less, preferably about 80 Shore D or less,and more preferably about 70 Shore D or less. In yet another embodiment,the hardness of the intermediate layer is about 50 Shore D or greater,preferably about 55 Shore D or greater. In one embodiment, theintermediate layer hardness is from about 55 Shore D to about 65 ShoreD. The intermediate layer may also be about 65 Shore D or greater.

When the intermediate layer is intended to be harder than the corelayer, the ratio of the intermediate layer hardness to the core hardnesspreferably about 2 or less. In one embodiment, the ratio is about 1.8 orless. In yet another embodiment, the ratio is about 1.3 or less.

As with the core and intermediate layers, the cover hardness may varydepending on the construction and desired characteristics of the golfball. The ratio of cover hardness to inner ball hardness is a primaryvariable used to control the aerodynamics of a ball and, in particular,the spin of a ball. In general, the harder the inner ball, the greaterthe driver spin and the softer the cover, the greater the driver spin.

For example, when the intermediate layer is intended to be the hardestpoint in the ball, e.g., about 50 Shore D to about 75 Shore D, the covermaterial may have a hardness of about 20 Shore D or greater, preferablyabout 25 Shore D or greater, and more preferably about 30 Shore D orgreater, as measured on the slab. In another embodiment, the coveritself has a hardness of about 30 Shore D or greater. In particular, thecover may be from about 30 Shore D to about 60 Shore D. In oneembodiment, the cover has a hardness of about 40 Shore D to about 65Shore D. In another embodiment, the cover has a hardness less than about45 Shore D, preferably less than about 40 Shore D, and more preferablyabout 25 Shore D to about 40 Shore D. In one embodiment, the cover has ahardness from about 30 Shore D to about 40 Shore D.

In this embodiment when the outer cover layer is softer than theintermediate layer or inner cover layer, the ratio of the Shore Dhardness of the outer cover material to the intermediate layer materialis about 0.8 or less, preferably about 0.75 or less, and more preferablyabout 0.7 or less. In another embodiment, the ratio is about 0.5 orless, preferably about 0.45 or less.

In yet another embodiment, the ratio is about 0.1 or less when the coverand intermediate layer materials have hardnesses that are substantiallythe same. When the hardness differential between the cover layer and theintermediate layer is not intended to be as significant, the cover mayhave a hardness of about 55 Shore D to about 65 Shore D. In thisembodiment, the ratio of the Shore D hardness of the outer cover to theintermediate layer is about 1.0 or less, preferably about 0.9 or less.

The cover hardness may also be defined in terms of Shore C. For example,the cover may have a hardness of about 70 Shore C or greater, preferablyabout 80 Shore C or greater. In another embodiment, the cover has ahardness of about 95 Shore C or less, preferably about 90 Shore C orless.

In another embodiment, the cover layer is harder than the intermediatelayer. In this design, the ratio of Shore D hardness of the cover layerto the intermediate layer is about 1.33 or less, preferably from about1.14 or less.

When a two-piece ball is constructed, the core may be softer than theouter cover. For example, the core hardness may range from about 30Shore D to about 50 Shore D, and the cover hardness may be from about 50Shore D to about 80 Shore D. In this type of construction, the ratiobetween the cover hardness and the core hardness is preferably about1.75 or less. In another embodiment, the ratio is about 1.55 or less.Depending on the materials, for example, if a composition of theinvention is acid-functionalized wherein the acid groups are at leastpartially neutralized, the hardness ratio of the cover to core ispreferably about 1.25 or less.

Compression

Compression values are dependent on the diameter of the component beingmeasured. The Atti compression of the core, or portion of the core, ofgolf balls prepared according to the invention is preferably less thanabout 80, more preferably less than about 75. As used herein, the terms“Atti compression” or “compression” are defined as the deflection of anobject or material relative to the deflection of a calibrated spring, asmeasured with an Atti Compression Gauge, that is commercially availablefrom Atti Engineering Corp. of Union City, N.J. Atti compression istypically used to measure the compression of a golf ball. In anotherembodiment, the core compression is from about 40 to about 80,preferably from about 50 to about 70. In yet another embodiment, thecore compression is preferably below about 50, and more preferably belowabout 25.

In an alternative, low compression embodiment, the core has acompression less than about 20, more preferably less than about 10, andmost preferably, 0. As known to those of ordinary skill in the art,however, the cores generated according to the present invention may bebelow the measurement of the Atti Compression Gauge. In an embodimentwhere the core is hard, the compression may be about 90 or greater. Inone embodiment, the compression of the hard core ranges from about 90 toabout 100.

The core of the present invention may also have a Soft Center DeflectionIndex (SCDI) compression of less than about 160, more preferably,between about 40 and about 160, and most preferably, between about 60and about 120.

In one embodiment, golf balls of the invention preferably have an Atticompression of about 55 or greater, preferably from about 60 to about120. In another embodiment, the Atti compression of the golf balls ofthe invention is at least about 40, preferably from about 50 to 120, andmore preferably from about 60 to 100. In yet another embodiment, thecompression of the golf balls of the invention is about 75 or greaterand about 95 or less. For example, a preferred golf ball of theinvention may have a compression from about 80 to about 95.

Initial Velocity and COR

There is currently no USGA limit on the COR of a golf ball, but theinitial velocity of the golf ball cannot exceed 250±5 feet/second(ft/s). Thus, in one embodiment, the initial velocity is about 245 ft/sor greater and about 255 ft/s or greater. In another embodiment, theinitial velocity is about 250 ft/s or greater. In one embodiment, theinitial velocity is about 253 ft/s to about 254 ft/s. In yet anotherembodiment, the initial velocity is about 255 ft/s. While the currentrules on initial velocity require that golf ball manufacturers staywithin the limit, one of ordinary skill in the art would appreciate thatthe golf ball of the invention would readily convert into a golf ballwith initial velocity outside of this range.

As a result, of the initial velocity limitation set forth by the USGA,the goal is to maximize COR without violating the 255 ft/s limit. In aone-piece solid golf ball, the COR will depend on a variety ofcharacteristics of the ball, including its composition and hardness. Fora given composition, COR will generally increase as hardness isincreased. In a two-piece solid golf ball, e.g., a core and a cover, oneof the purposes of the cover is to produce a gain in COR over that ofthe core. When the contribution of the core to high COR is substantial,a lesser contribution is required from the cover. Similarly, when thecover contributes substantially to high COR of the ball, a lessercontribution is needed from the core.

The present invention contemplates golf balls having CORs from about 0.7to about 0.85. In one embodiment, the COR is about 0.75 or greater,preferably about 0.78 or greater. In another embodiment, the ball has aCOR of about 0.8 or greater.

In addition, the inner ball preferably has a COR of about 0.780 or more.In one embodiment, the COR is about 0.790 or greater.

Flexural Modulus

Accordingly, it is preferable that the golf balls of the presentinvention have an intermediate layer with a flexural modulus of about500 psi to about 500,000 psi. More preferably, the flexural modulus ofthe intermediate layer is about 1,000 psi to about 250,000 psi. Mostpreferably, the flexural modulus of the intermediate layer is about2,000 psi to about 200,000 psi.

The flexural moduli of the cover layer is preferably about 2,000 psi orgreater, and more preferably about 5,000 psi or greater. In oneembodiment, the flexural modulus of the cover is from about 10,000 psito about 150,000 psi. More preferably, the flexural modulus of the coverlayer is about 15,000 psi to about 120,000 psi. Most preferably, theflexural modulus of the cover layer is about 18,000 psi to about 110,000psi. In another embodiment, the flexural moduli of the cover layer isabout 100,000 psi or less, preferably about 80,000 or less, and morepreferably about 70,000 psi or less. In one embodiment, when the coverlayer has a hardness of about 50 Shore D to about 60 Shore D, the coverlayer preferably has a flexural modulus of about 55,000 psi to about65,000 psi.

In one embodiment, the ratio of the flexural modulus of the intermediatelayer to the cover layer is about 0.003 to about 50. In anotherembodiment, the ratio of the flexural modulus of the intermediate layerto the cover layer is about 0.006 to about 4.5. In yet anotherembodiment, the ratio of the flexural modulus of the intermediate layerto the cover layer is about 0.11 to about 4.5.

In one embodiment, the compositions of the invention are used in a golfball with multiple cover layers having essentially the same hardness,but differences in flexural moduli. In this aspect of the invention, thedifference between the flexural moduli of the two cover layers ispreferably about 5,000 psi or less. In another embodiment, thedifference in flexural moduli is about 500 psi or greater. In yetanother embodiment, the difference in the flexural moduli between thetwo cover layers, wherein at least one is reinforced is about 500 psi toabout 10,000 psi, preferably from about 500 psi to about 5,000 psi. Inone embodiment, the difference in flexural moduli between the two coverlayers formed of unreinforced or unmodified materials is about 1,000 psito about 2,500 psi.

Specific Gravity

The specific gravity of a cover or intermediate layer including thepolyurethane or polyurea compositions of the invention is preferably atleast about 0.7.

Adhesion Strength

The adhesion, or peel, strength of the polyurethane and polyureacompositions of the invention is preferably about 5 lb_(f)/in orgreater. In one embodiment, the adhesion strength is about 25 lb_(f)/inor less. For example, the adhesion strength is preferably about 10lb_(f)/in or more and about 20 lb_(f)/in or less. In another embodiment,the adhesion strength is about 20 lb_(f)/in or greater, preferably about24 lb_(f)/in or greater. In yet another embodiment, the adhesionstrength is about 26 lb_(f)/in or greater. In still another embodiment,the adhesion strength is about 20 lb_(f)/in to about 30 lb_(f)/in.

Shear/Cut Resistance

The cut resistance of a golf ball cover may be determined using a sheartest having a scale from 1 to 9 assessing damage and appearance. In oneembodiment, the damage rank is preferably about 3 or less, morepreferably about 2 or less. In another embodiment, the damage rank isabout 1 or less. The appearance rank of a golf ball of the invention ispreferably about 3 or less. In one embodiment, the appearance rank isabout 2 or less, preferably about 1 or less.

Light Stability

As discussed above, the compositions of the invention may be inherentlylight stable, i.e., include no aromatic components The light stabilityof the cover may be quantified by the difference in yellowness index(*Y1), i.e., yellowness measured after a predetermined exposuretime−yellowness before exposure. In one embodiment, the *Y1 is about 10or less after 5 days (120 hours) of exposure, preferably about 6 or lessafter 5 days of exposure, and more preferably about 4 or less after 5days of exposure. In one embodiment, the *Y1 is about 2 or less after 5days of exposure, and more preferably about 1 or less after 5 days ofexposure.

The difference in the b chroma dimension (*b*, yellow to blue) is also away to quantify the light stability of the cover. In one embodiment, the*b* is about 4 or less after 5 days (120 hours) of exposure, preferablyabout 3 or less after 5 days of exposure, and more preferably about 2 orless after 5 days of exposure. In one embodiment, the *b* is about 1 orless after 5 days of exposure.

EXAMPLES

The following non-limiting examples are merely illustrative of thepreferred embodiments of the present invention, and are not to beconstrued as limiting the invention, the scope of which is defined bythe appended claims. Parts are by weight unless otherwise indicated.

Examples 1–2 Saturated Polyurethane Golf Ball Cover

Table 3 illustrates the components used to make a saturated polyurethanegolf ball cover composition.

TABLE 3 SATURATED POLYURETHANE COMPOSITIONS Example 1 Example 2Chemicals Weight (g) Weight (g) IPDI Prepolymer* 458.73 H₁₂MDIPrepolymer** 458.73 1,4-Butanediol 42.75 42.75 HCC-19584 ColorDispersion*** 17.55 17.55 *Prepolymer is the reaction product ofisophorone diisocyanate and polytetramethylene ether glycol.**Prepolymer is the reaction product of 4,4′-dicyclohexylmethanediisocyanate and polytetramethylene ether glycol. ***HCC-19584 is awhite-blue color dispersion manufactured by Harwick Chemical Corporation

A golf ball was made having the cover formulated from the compositionsabove following the teachings of U.S. Pat. No. 5,733,428. The physicalproperties and the ball performance results are listed in Table 4.

TABLE 4 PHYSICAL PROPERTIES Physical Properties Example 1 Example 2Cover Hardness 68 54 Weight (g) 45.20 45.58 Compression 103 89 ShearResistance Good Good Color Stability Comparable to Comparable toSURLYN ® SURLYN ®

The molded balls from the above Example 2 composition listed in Table 3were further subject to a QUV test as described below:

Method:

ASTM G 53-88 “Standard Practice for Operating Light and Water-ExposureApparatus (Fluorescent UV-Condensation Type) for Exposure of NonmetallicMaterials” was followed with certain modifications as described below:

Six balls of each variety under evaluation were placed in custom madegolf ball holders and inserted into the sample rack of a Q-PANEL modelOUV/SER Accelerated Weathering Tester manufactured by Q-Panel LabProducts of Cleveland, Ohio. The sample holders were constructed suchthat each ball was approximately 1.75 inches from a UVA-340 bulb, at itsclosest point. The weathering tester was then cycled every four hoursbetween the following two sets of conditions (for the specified totallength of time 24, 48, and 120 hours):

-   -   Condition #1: water bath temperature of about 50° C. with the UV        lamps on, set and controlled at an irradiance power of 1.00        W/m²/nm.    -   Condition #2: water bath temperature of about 40° C. with the UV        lamps turned off.        Color was measured before weathering and after each time cycle        using a BYK-Gardner Model TCS II sphere type Spectrophotometer        equipped with a 25 mm port. A D65/10° illumination was used in        the specular reflectance included mode.

The test results for the molded balls after 24 hours of UV exposure aretabulated in Table 5, wherein ΔL* equals the difference in L dimension(light to dark), Δa* equals the difference in the a chroma dimension(red to green), Δb* equals the difference in the b chroma dimension(yellow to blue), ΔC* equals the combined chroma difference (a* and b*scales), hue and saturation, ΔH* equals the total hue difference,excluding effects of saturation and luminescence, ΔE* equals the totalcolor difference, ΔW1 equals the difference in the whiteness index, andΔY1 and the difference in the yellowness index.

TABLE 5 UV STABILITY DATA Sample ΔL* Δa* Δb* ΔC* ΔH* ΔE*ab ΔW1 (E313)ΔY1 (D1925) Example 2 −0.21 −0.30 1.54 −1.26 −0.94 1.58 −9.07 2.99Molded Aromatic −17.27 11.36 46.14 47.31 4.36 50.56 −142.35 93.80Polyurethane Molded −0.39 −0.25 0.91 −0.76 −0.55 1.02 −6.19 1.69SURLYN ®

The test results for the molded balls after 48 hours of UV exposure areillustrated in Table 6.

TABLE 6 UV STABILITY DATA Sample ΔL* Δa* Δb* ΔC* ΔH* ΔE*ab ΔW1 (E313)ΔY1 (D1925) Example 2 −0.48 −0.37 2.54 −2.02 −1.59 2.61 −15.16 4.98Molded Aromatic −23.46 15.01 42.75 45.18 3.44 51.02 −127.75 98.96Polyurethane Molded −0.54 −0.39 1.43 −1.18 −0.91 1.58 −9.50 2.66SURLYN ®

The test results for the molded balls after 120 hours of UV exposure areillustrated in Table 7.

TABLE 7 UV STABILITY DATA Sample ΔL* Δa* Δb* ΔC* ΔH* ΔE*ab ΔW1 (E313)ΔY1 (D1925) Example 2 −0.92 −0.46 5.87 −3.01 −5.06 5.96 −33.72 11.68Molded Aromatic −30.06 16.80 33.37 37.29 2.11 47.95 −107.12 94.42Polyurethane Molded −0.99 −0.85 4.06 −2.91 −2.96 4.26 −24.88 7.73SURLYN ®

Example 3 H₁₂MDI Polyether Urethane Elastomer

A golf ball was made having the cover formulated from the composition inTable 8 including H₁₂MDI polyether urethane elastomer.

TABLE 8 H₁₂MDI POLYETHER URETHANE ELASTOMER COMPOSITION Example 3Chemical Components Weight (g) H₁₂MDI/PTMEG Prepolymer, 9.1% NCO 462.641,4-Butanediol 26.02 S28755PST3 Color Dispersion* 31.25 Dabco ® T-12Catalyst 0.65 *S28755PST3 color dispersion is manufactured by PPGIndustries.

The physical properties and the ball performance results are listed inTable 9. A control ball made with an aromatic polyurethane is alsoincluded in Table 9 for comparison purposes.

TABLE 9 PHYSICAL PROPERTIES Ball Properties/Ball Types Aromatic ControlExample 3 Nameplate Average 1.684 1.683 Equator Average 1.685 1.683Weight Average, oz 1.608 1.594 Compression Average 87 86 Cover Hardness,Shore C 81 79 CoR @ 125 ft/sec 0.810 0.809 Impact Durability, 600 Hits 1failed @ 369 hits no failure 1 failed @ 400 hits Cold Crack Test, 5° F.no failure no failure Light Stability 5 Days QUV Test ΔY1 1.6 Δb* 0.8Live Golfer Shear Test* Damage Rank 3 2 Appearance Rank 3 2 *Rating ofShear Test: Based on a scale of 1–9, 1 is the best, 9 is the worst.

Example 4 H₁₂MDI Polycaprolactone Urethane Elastomer

A golf ball was made having the cover formulated from the composition inTable 10 including H₁₂MDI polycaprolactone urethane elastomer.

TABLE 10 H₁₂MDI POLYCAPROLACTONE URETHANE ELASTOMER COMPOSITION Example4 Chemical Components Weight (g) H₁₂MDI/Polycaprolactone Prepolymer,9.1% NCO 462.64 1,4-Butanediol 26.02 S28755PST3 Color Dispersion* 31.25Tinuvin ® 292 HALS 1.30 Dabco ® T-12 Catalyst 0.65 *S28755PST3 colordispersion is manufactured by PPG Industries.

The physical properties and the ball performance results are listed inTable 11. A control ball made with an aromatic polyurethane is alsoincluded in Table 11 for comparison purposes.

TABLE 11 PHYSICAL PROPERTIES Ball Properties/Ball Types Aromatic ControlExample 4 Nameplate Average 1.678 1.683 Equator Average 1.680 1.683Weight Average, oz 1.605 1.607 Compression Average 90 87 Cover Hardness,Shore C 82 83 CoR @ 125 ft/sec 0.811 0.808 Impact Durability, 600 Hits 1failed @ 419, 488, 1 failed @ 535 hit 510, 512, 521 hits Cold CrackTest, 5° F. no failure no failure Light Stability 3 Hour QUV Test 5 DaysQUV Test ΔY1 79.1 1.0 Δb* 40.8 0.5 Live Golfer Shear Test* Damage Rank 17 Appearance Rank 1 7 *Rating of Shear Test: Based on a scale of 1–9, 1is the best, 9 is the worst.

Example 5 H₁₂MDI Polyester Urethane Elastomer

A golf ball was made having the cover formulated from the composition inTable 12 including H₁₂MDI polyester urethane elastomer.

TABLE 12 H₁₂MDI POLYESTER URETHANE ELASTOMER COMPOSITION Example 5Chemical Components Weight (g) H₁₂MDI/polyhexamethylene butyleneadipate, 8.07% 521.69 NCO 1,4-Butanediol 24.01 S28755PST3 ColorDispersion* 35.00 Dabco ® T-12 Catalyst 0.73 *S28755PST3 colordispersion is manufactured by PPG Industries.

The physical properties and the ball performance results are listed inTable 13. A control ball made with an aromatic polyurethane is alsoincluded in Table 13 for comparison purposes.

TABLE 13 PHYSICAL PROPERTIES Ball Properties/Ball Types Aromatic ControlExample 5 Nameplate Average 1.684 1.683 Equator Average 1.683 1.680Weight Average, oz 1.607 1.610 Compression Average 87 88 Cover Hardness,Shore C 81 84 CoR @ 125 ft/sec 0.806 0.803 Impact Durability, 600 Hitsno failure no failure Cold Crack Test, 5° F. no failure no failure LightStability 3 Hour QUV Test 5 Days QUV Test ΔY1 79.1 1.6 Δb* 40.8 0.8 LiveGolfer Shear Test* Damage Rank 1 3 Appearance Rank 1 2 *Rating of ShearTest: Based on a scale of 1–9, 1 is the best, 9 is the worst.

Example 6 H₁₂MDI Polyether Urethane/Urea Elastomer

A golf ball was made having the cover formulated from the composition inTable 14 including H₁₂MDI polyether urethane/urea elastomer.

TABLE 14 H₁₂MDI POLYETHER URETHANE/UREA ELASTOMER COMPOSITION Example 6Chemical Components Weight (g) H₁₂MDI/PTMEG Prepolymer, 7.9% NCO 532.91Clearlink 1000 152.95 HCC-19584 Color Dispersion* 24.88 Dabco ® T-12Catalyst 0.07 *HCC-19584 color dispersion is manufactured by PolyOneCorporation.

The physical properties and the ball performance results are listed inTable 15. A control ball made with an aromatic polyurethane is alsoincluded in Table 15 for comparison purposes.

TABLE 15 PHYSICAL PROPERTIES Ball Properties/Ball Types Aromatic ControlExample 6 Nameplate Average 1.683 1.687 Equator Average 1.683 1.682Weight Average, oz 1.608 1.596 Compression Average 88 89 Cover Hardness,Shore C 81 86 CoR @ 125 ft/sec 0.805 0.806 Impact Durability, 600 Hitsno failure no failure Cold Crack Test, 5° F. no failure no failure LightStability 3 Hour QUV Test 5 Days QUV Test ΔY1 79.1 0.4 Δb* 40.8 0.1 LiveGolfer Shear Test* Damage Rank 1 1 Appearance Rank 1 1 *Rating of ShearTest: Based on a scale if 1–9, 1 is the best, 9 is the worst.

Example 7 Low Free HDI Polyether Urethane Elastomer Composition

A golf ball was made having the cover formulated from the composition inTable 16 including low free HDI polyether urethane elastomer.

TABLE 16 LOW FREE HDI POLYETHER URETHANE ELASTOMER COMPOSITION Example 7Chemical Components Weight (g) HDI/PTMEG Prepolymer, 5.77% NCO 729.641,4-Butanediol 17.21 S28755PST3 Color Dispersion* 47.70 Dabco ® T-12Catalyst 0.48 *S28755PST3 color dispersion is manufactured by PPGIndustries.

The physical properties and the ball performance results are listed inTable 17. A control ball made with an aromatic polyurethane is alsoincluded in Table 17 for comparison purposes.

TABLE 17 PHYSICAL PROPERTIES Ball Properties/Ball Types Aromatic ControlExample 7 Nameplate Average 1.684 1.685 Equator Average 1.683 1.683Weight Average, oz 1.607 1.602 Compression, Average 89 89 CoverHardness, Shore C 81 86 CoR @ 125 ft/sec 0.804 0.809 Impact Durability,600 Hits 1 failed @ 550 hits no failure Cold Crack Test, 5° F. nofailure no failure Light Stability 3 Hour QUV Test 5 Days QUV Test ΔY179.1 1.9 Δb* 40.8 0.8 Live Golfer Shear Test* Damage Rank 1 3 AppearanceRank 1 3 *Rating of Shear Test: Based on a scale of 1–9, 1 is the best,9 is the worst.

Example 8 H₁₂MDI/Dimerate Polyester Urethane Elastomer

A golf ball was made having the cover formulated from the composition inTable 18 including H₁₂MDI/dimerate polyester urethane elastomer.

TABLE 18 H₁₂MDI/DIMERATE POLYESTER URETHANE ELASTOMER COMPOSITIONExample 8 Chemical Components Weight (g) H₁₂MDI/Hydroxy-TerminatedDimerate 462.64 Polyester* Prepolymer, 9.10% NCO 1,4-Butanediol 26.02S28755PST3 Color Dispersion** 31.25 Dabco ® T-12 Catalyst 0.65*Hydroxy-terminated dimerate polyester polyol is manufactured byUniqema. **S28755PST3 color dispersion is manufactured by PPGIndustries.

The physical properties and the ball performance results are listed inTable 19. A control ball made with an aromatic polyurethane is alsoincluded in Table 19 for comparison purposes.

TABLE 19 PHYSICAL PROPERTIES Ball Properties/Ball Types Aromatic ControlExample 8 Nameplate Average 1.684 1.689 Equator Average 1.683 1.683Weight Average, oz 1.607 1.605 Compression Average 89 90 Cover Hardness,Shore C 82 84 CoR @ 125 ft/sec 0.807 0.807 Impact Durability, 600 Hits 1failed @ 431, no failure 524, 539, 578 hits Cold Crack Test, 5° F. nofailure no failure Light Stability 5 Days QUV Test ΔY1 8.8 Δb* 5.2 LiveGolfer Shear Test* Damage Rank 1 1 Appearance Rank 1 2 *Rating of ShearTest: Based on a scale of 1–9, 1 is the best, 9 is the worst.

Example 9 H₁₂MDI Polyether Urea Cured with Diol

A golf ball was made having the cover formulated from a compositionincluding a prepolymer formed of H₁₂MDI and polyoxyalkylene, having amolecular weight of about 2000, cured with 1,4-butanediol. The physicalproperties and the ball performance results are listed in Table 20. Agolf ball similar to Example 2, a light stable, aliphatic polyurethane,was used for comparison purposes.

TABLE 20 PHYSICAL PROPERTIES Aliphatic Polyurethane Ball Properties/BallTypes Control Example 9 Nameplate Average 1.686 1.684 Equator Average1.684 1.683 Weight Average, oz 1.599 1.595 Compression Average 86 86 CoR@ 125 ft/sec 0.807 0.805 Cold Crack Test, 5° F. no failure no failureLight Stability (5 Days QUV Test) ΔY1 3.2 0.8 Δb* 1.7 0.4 Live GolferShear Test* Damage Rank 3 2 Appearance Rank 3 2 *Rating of Shear Test:Based on a scale of 1–9, 1 is the best, 9 is the worst.

Example 10 H₁₂MDI Polyether Urea Cured with a Diamine

A golf ball was made having the cover formulated from a compositionincluding a prepolymer formed of H₁₂MDI and polyoxyalkylene, having amolecular weight of about 2000, cured with4,4′-bis-(sec-butylamino)-dicyclohexylmethane (Clearlink 1000). Thephysical properties and the ball performance results are listed in Table21. A golf ball similar to Example 2, a light stable, aliphaticpolyurethane, was used for comparison purposes.

TABLE 21 PHYSICAL PROPERTIES Light Stable Ball Properties/Ball TypesPolyurethane Control Example 10 Nameplate Average 1.683 1.686 EquatorAverage 1.681 1.684 Weight Average, oz 1.597 1.600 Compression Average89 92 CoR @ 125 ft/sec 0.807 0.815 Cold Crack Test, 5° F. no failure nofailure Light Stability (5 Days QUV Test) ΔY1 4.3 0.6 Δb* 2.4 0.3 LiveGolfer Shear Test* Damage Rank 3 1 Appearance Rank 3 1 *Rating of ShearTest: Based on a scale of 1–9, 1 is the best, 9 is the worst.

Examples 11–15 Modified Curative Blends

A pigment dispersion concentrate was prepared using components asoutlined in Table 22. A Cowles blade was used to achieve a pigmentdisperson of 6.0 on the Hegman scale.

TABLE 22 PIGMENT DISPERSION Weight Percent (of total Materialdispersion) 1,4-Butanediol¹ 69.44%  TiO₂ ² 23.42%  Ultramarine BluePigment³ 0.23% SILWET L-7210 wetting additive⁴ 0.10% Tinuvin 292⁵ 2.13%Tin Catalyst⁶ 4.68% ¹Obtained from Lyondel Corporation ²Obtained fromDupont Corporation ³Obtained from Whittaker, Clark, and Daniels⁴Polyalkeneoxide modified polydimethylsiloxane, obtained from CromptonCorporation ⁵Hindered Amine Light Stabilizer, obtained from Ciba-Geigy⁶Tin catalyst, obtained from Air Products.

The pigment dispersion concentrate was then blended with a curing agentand a freezing point depressing agent (with the exception of controlExample 11) to make a curative blend. The freezing point of the curativeblend was determined by cooling the material in an ice bath andrecording the solidification temperature. As shown in Table 23, theaddition of a freezing point depressing agent (Examples 12–15) loweredthe freezing point of the blend by at least about 14° F. as compared tothe pigment dispersion without a freezing point depressing agent.Example 12 demonstrates the use of ethylene glycol as a freezing pointdepressing agent, which lowered the freezing point of the pigmentdispersion by about 19° F.

TABLE 23 PHYSICAL PROPERTIES Weight Percent of Example Total 11 Curative(Con- Example Example Example Example Blend trol) 12 13 14 15 Pigment100% 90% 90% 90% 90% Disperson Ethylene — 10% — — — Glycol Dipropylene —— 10% — — Glycol Propylene — — — 10% — Glycol 2-methyl- — — — — 10% 1,3-propanen- diol Freezing 64° F. 45° F. 50° F. 50° F. 50° F. Point

In addition, the curative blend of Example 15 exhibited a softsemi-solid upon freezing as compared to the crystallized solid formed inthe control (Example 11).

Examples 16–20 Modified Curative Blends

A titanium white pigment dispersion was prepared according to theinvention as outlined in Table 24. A Cowles blade was used to achieve apigment disperson of 6.0 on the Hegman scale.

TABLE 24 PIGMENT DISPERSION Weight Percent (of total Materialdispersion) 1,4-Butanediol¹ 53.78% TiO₂ ² 46.02% SILWET L-7210 wettingadditive³  0.20% ¹Obtained from Lyondel Corporation ²Obtained fromDupont Corporation ³Polyalkeneoxide modified polydimethylsiloxane,obtained from Crompton Corporation

The pigment dispersion was then blended with a curing agent, a freezingpoint depressing agent (with the exception of the control Example 16),and a tin catalyst for faster reaction to make a curative blend. Thefreezing point of the curative blend was determined by cooling thematerial in an ice bath and recording the solidification temperature. Asshown in Table 25, the addition of a sufficient amount of freezing pointdepressing agent (Examples 18–20) lowered the freezing point of theblend by at least about 8° F. as compared to the pigment dispersionwithout a freezing point depressing agent. In addition, the curativeblend of Examples 18 and 19 exhibited a soft semi-solid upon freezing ascompared to the crystallized solid formed in the control (Example 16).

TABLE 25 PHYSICAL PROPERTIES Weight Percent of Example Total 16 Curative(Con- Example Example Example Example Blend trol) 17 18 19 20 Pigment57.3% 57.3% 57.3% 57.3% 57.3% Disperson 1,4 37.5% 36.8% 34.1% 30.7%23.8% butanediol 2-methyl- 0  0.7%  3.4%  6.8% 13.6% 1,3- propanen- diolTin  5.3%  5.3%  5.3%  5.3%  5.3% Catalyst Freezing 66° F. 66° F. 58° F.53° F. 42° F. Point

The curative blends of Examples 16–20 were placed in a freezer for 72hours with temperatures ranging from about −14° F. to about 14° F. Theblends were then thawed at room temperature. Table 26 shows the pigmentdispersion (as measured on the Hegman scale) of each blend afterthawing. Examples 19 and 20 demonstrated good pigment dispersion after afreeze/thaw cycle, which allows reuse without having to agitate at ahigh speed or mill grind.

TABLE 26 PIGMENT DISPERSION OF BLENDS AFTER THAWING Hegman Scale Example# Before Freezing After Freezing Example 16 (Control) 6.0 0 largeagglomerates Example 17 6.0 0 large agglomerates Example 18 6.0 0 lessagglomerates Example 19 6.0 4.0 very smooth, homogenous Example 20 6.05.0 very smooth, homogenous

Examples 21–25 Modified Curative Blends

An organic red pigment dispersion was prepared according to theinvention as outlined in Table 27. A Cowles blade was used to achieve apigment disperson of 5.0 on the Hegman scale.

TABLE 27 PIGMENT DISPERSION Weight Percent (of total Materialdispersion) 1,4-Butanediol¹ 78.26% Novoperm Red Pigment¹ 21.60% SILWETL-7210 wetting additive³  0.14% ¹Obtained from Lyondel Corporation²Obtained from Clariant Corporation ³Polyalkeneoxide modifiedpolydimethylsiloxane, obtained from Crompton Corporation

The pigment dispersion was then blended with a curing agent and afreezing point depressing agent (with the exception of the controlExample 21) to make a curative blend. The freezing point of the curativeblend was determined by cooling the material in an ice bath andrecording the solidification temperature. As shown in Table 28, theaddition of a sufficient amount of freezing point depressing agent(Examples 23–25) lowered the freezing point of the blend by at leastabout 8° F. as compared to the pigment dispersion without a freezingpoint depressing agent. In addition, the curative blend of Examples 18and 19 exhibited a soft semi-solid upon freezing as compared to thecrystallized solid formed in the control (Example 21).

TABLE 28 PHYSICAL PROPERTIES Weight Percent of Example Total 21 Curative(Con- Example Example Example Example Blend trol) 22 23 24 25 Pigment66.7% 66.7% 66.7% 66.7% 66.7% Disperson 1,4- 33.3% 32.5% 29.1% 24.8%16.2% butanediol 2-methyl- 0  0.8%  4.2%  8.5% 17.1% 1,3- propanen- diolFreezing 66° F. 66° F. 58° F. 53° F. 42° F. Point

The curative blends of Examples 21–25 were placed in a freezer for 72hours with temperatures ranging from about −14° F. to about 14° F. Theblends were then thawed at room temperature. Table 29 shows the pigmentdispersion (as measured on the Hegman scale) of each blend afterthawing. Examples 24 and 25 demonstrated good pigment dispersion after afreeze/thaw cycle, which allows reuse without having to agitate at ahigh speed or mill grind.

TABLE 29 PIGMENT DISPERSION OF BLENDS AFTER THAWING Hegman Scale Example# Before Freezing After Freezing Example 21 (Control) 5.0 0 largeagglomerates Example 22 5.0 0 large agglomerates Example 23 5.0 0 lessagglomerates Example 24 5.0 4.0 very smooth, homogenous Example 25 5.05.0 very smooth, homogenous

Example 26 Golf Ball Cover with Modified Curative Blend

Curative blend samples were prepared with 90 parts by weight1,4-butanediol and 10 parts by weight of freezing point depressing agent2-methyl-1,3-propanediol. After overnight refrigeration, the samplesremained in liquid form. The curative blend began to solidify at about40° F. Upon thawing at room temperature, the samples had a pigmentdispersion of about 6.0 or greater on the Hegman sclae. In addition,comparison of the samples with control 1,4-butanediol curing agentscontaining no freezing point depressing agents showed that the sampleshad a noticeable improvement for setting and separation.

Samples were frozen and shipped overnight for golf ball formulation.Covers were formed onto inner components using an H₁₂MDI/PTMEG 2000prepolymer (9.1 percent NCO content) cured with the sample curativeblend. Control balls were created with a cover formed onto the sameinner components as Example 26, but the cover included an H₁₂MDI/PTMEG2000 prepolymer (9.1 percent NCO content) cured with an unmodified1,4-butanediol curing agent. Table 30 demonstrates that the addition ofthe freezing point depressing agent in the curative blend (Example 26)does not result in the degradation of ball performance or weakening ofphysical properties as the results for both the control and Example 26are substantially the same.

TABLE 30 PHYSICAL PROPERTIES Ball Properties/Ball Types Control Example26 Nameplate Average 1.682 1.682 Equator Average 1.680 1.680 WeightAverage, oz 1.593 1.593 Compression Average 87 86 CoR @ 125 ft/sec 0.8050.804 Impact Durability Test, 600 no failure no failure Hits Cold CrackTest, 5° F. no failure no failure

All patents and patent applications cited in the foregoing text areexpressly incorporate herein by reference in their entirety. Theinvention described and claimed herein is not to be limited in scope bythe specific embodiments herein disclosed, since these embodiments areintended as illustrations of several aspects of the invention. Anyequivalent embodiments are intended to be within the scope of thisinvention. Indeed, various modifications of the invention in addition tothose shown and described herein will become apparent to those skilledin the art from the foregoing description. Such modifications are alsointended to fall within the scope of the appended claims.

1. A golf ball comprising a core and a cover, wherein the cover isformed from a composition comprising: a saturated polyurethaneprepolymer formed from the reaction product of a saturated isocyanateand a saturated polyol; and a saturated curative blend formed from atleast one saturated curing agent and at least one compatible saturatedfreezing point depressing agent, wherein the saturated curative blendcomprises a pigment contained in a grind vehicle.
 2. The golf ball ofclaim 1, wherein the at least one curing agent has a first freezingpoint and the curative blend has a second freezing point, and whereinthe second freezing point is less than the first freezing point by about5° F. or greater.
 3. The golf ball of claim 2, wherein the at least onecuring agent has a first freezing point and the curative blend has asecond freezing point, and wherein the second freezing point is lessthan the first freezing point by about 10° F. or greater.
 4. The golfball of claim 3, wherein the at least one curing agent has a firstfreezing point and the curative blend has a second freezing point, andwherein the second freezing point is less than the first freezing pointby about 15° F. or greater.
 5. The golf ball of claim 1, wherein thefreezing point depressing agent has a freezing point of about 10° F. orless.
 6. The golf ball of claim 1, wherein the freezing point depressingagent has a freezing point from about −10° F. to about 100° F.
 7. Thegolf ball of claim 1, wherein the freezing point depressing agentcomprises hydroxy-terminated freezing point depressing agents selectedfrom the group consisting of 1,3-propanediol, 2-methyl-1,3-propanediol,2-methyl-1,4-butanediol, 1,2-butanediol, 1,3-butanediol, ethyleneglycol, diethylene glycol, 1,5-pentanediol, polytetramethylene glycol,propylene glycol, and mixtures thereof.
 8. The golf ball of claim 1,wherein the freezing point depressing agent is present in an amount ofabout 8 percent or greater by weight of the curative blend.
 9. The golfball of claim 8, wherein the freezing point depressing agent is presentin an amount of about 10 percent or greater by weight of the curativeblend.
 10. The golf ball of claim 1, wherein the curative blend has apigment dispersion of about 4 or greater on the Hegman scale.
 11. Thegolf ball of claim 10, wherein the curative blend has a pigmentdispersion of about 5 or greater on the Hegman scale.
 12. A golf ballcomprising a core and a light stable cover, wherein the cover is formedfrom a composition comprising: a polyurethane prepolymer formed from thereaction product of an isocyanate and a polyol; and a pigment dispersedin a curative blend comprising at least one curing agent having a firstfreezing point and at least one freezing point depressing agent having asecond freezing point of about −10° F. to about −100° F., wherein thepigment is contained in a grind vehicle.
 13. The golf ball of claim 12,wherein the curative blend has a pigment dispersion of about 4 orgreater after a freeze/thaw cycle.
 14. The golf ball of claim 12,wherein the second freezing point is less than the first freezing pointby about 10° F. or greater.
 15. The golf ball of claim 12, wherein thefreezing point depressing agent is present in an amount of about 10percent or greater by weight of the curative blend.
 16. The golf ball ofclaim 12, wherein the cover layer is formed from casting, injectionmolding, or reaction injection molding.
 17. The golf ball of claim 12,wherein the cover has a thickness of about 0.02 inches to about 0.035inches.
 18. The golf ball of claim 12, wherein the polyol is selectedfrom the group consisting of saturated polyether polyols, saturatedpolycaprolactone polyols, saturated polyester polyols, saturatedpolycarbonate polyols, saturated hydrocarbon polyols, aliphatic polyols,and mixtures thereof.
 19. The golf ball of claim 12, wherein the atleast one curing agent is selected from the group consisting of ethyleneglycol; diethylene glycol; polyethylene glycol; propylene glycol;2-methyl-1,3-propanediol; 2,-methyl-1,4-butanediol; dipropylene glycol;polypropylene glycol; 1,2-butanediol; 1,3-butanediol; 1,4-butanediol;2,3-butanediol; 2,3-dimethyl-2,3-butanediol; trimethylolpropane;cyclohexyldimethylol; triisopropanolamine;tetra-(2-hydroxypropyl)-ethylene diamine; diethylene glycoldi-(aminopropyl)ether; 1,5-pentanediol; 1,6-hexanediol;1,3-bis-(2-hydroxyethoxy)cyclohexane; 1,4-cyclohexyldimethylol;1,3-bis-[2-(2-hydroxyethoxy)ethoxy]cyclohexane;1,3-bis-{2-[2-(2-hydroxyethoxy)ethoxy]ethoxy}cyclohexane;trimethylolpropane; polytetramethylene ether glycol; and mixturesthereof.
 20. The golf ball of claim 12, wherein the composition furthercomprises at least one catalyst, at least one light stabilizer, at leastone defoaming agent, at least one acid functionalized moiety, at leastone fragrance component, or combinations thereof.
 21. A golf ballcomprising a core and a light stable cover, wherein the cover is formedfrom a composition comprising: a polyurethane prepolymer formed from thereaction product of an isocyanate and a polyol; and a pigment dispersedin a solvent free curative blend comprising a curing agent and afreezing point depressing agent, wherein the freezing point depressingagent has a freezing point of about −10° F. to about −120° F., andwherein the pigment is contained in a grind vehicle.
 22. The golf ballof claim 21, wherein the curative blend has a freezing point of about−10° F. to about −100° F.
 23. The golf ball of claim 22, wherein thecurative blend has a freezing point of about −30° F. to about −70° F.24. The golf ball of claim 21, wherein the polyurethane prepolymer issaturated.
 25. The golf ball of claim 21, wherein the freezing pointdepressing agent is included in the curative blend in an amount of about5 percent or greater by weight of the curative blend.
 26. The golf ballof claim 25, wherein the freezing point depressing agent is included inthe curative blend in an amount of about 8 percent or greater by weightof the curative blend.